Microsoft Surface line up has come a long way in not only design and performance, but also in public perception. When it launched in 2012, there was no device like it on the market and people weren't sure what to make of it. Was it a tablet or a notebook, and could you really have the best of both in one device? But now companies such as Dell, Lenovo, Toshiba, Asus, HP and even Apple have jumped on board with the tablet-as-a-notebook concept, reinforcing Microsoft's strategy. \n\nWith each iteration, Microsoft has improved on the Surface, and the Surface Pro 4 is certainly no exception. With a brilliant display, impressive specs, enterprise-ready features and a sleek design, it's ready for work or play -- and it's the best Surface yet. \n\nDesign: As slim as it can get\n\nEvery Surface design closely resembles the one that came before it, and that is true when you compare the Surface Pro 4 and Surface Pro 3. The Pro 4 is slightly thinner than the Pro 3, but only by .03 inches. and at 1.73 pounds, its only .03 pounds lighter than its predecessor. Devices can get only so slim before you start to sacrifice features like a full USB port, and the Surface Pro 4 is certainly slim and light enough to carry around wherever you need to take it. The biggest changes you'll find are in the specs and accessories. \n\nThe device features the familiar magnesium silver chassis, which gives it a high-end, stylish design. If you liked the design of past Surface models, you'll be more than happy with the looks of the Surface Pro 4. Around the edges of the device, are all the familiar ports including a full-sized USB 3.0, microSD card reader, headphone jack, Mini DisplayPort and the SurfaceConnect charging port. You'll find the front-facing 5 megapixel camera on the top of the bezel. On the back of the device, there is an 8 megapixel rear-facing camera with 1080p HD video recording capabilities. Overall, all the necessary ports are there and the design, while mostly unchanged, is still sleek and stylish. \n\nType cover and pen impress\n\nThe type cover -- which is still sold separately -- magnetically attaches to the base of the device, as it has with previous iterations, but the Surface Pro 4 brings some design improvements. One notable difference is that the keystrokes aren't as noisy as the last type cover, making it easier to type during a conference, on a flight or in a meeting without feeling like you are disturbing your neighbors. \n\nThe chicklet-style keys are also set further apart, with a 1.4mm key travel, which is the same as the MacBook Pro. Overall, the minor changes make the type cover feel as comfortable as a keyboard you'd find on a traditional laptop. It's also compatible with the Surface Pro 3 and you can opt to purchase a version with a built-in fingerprint scanner for added authentication security. \n\nThe trackpad is also larger and features a new glass surface -- and it's responsive. It's hard to find a trackpad that can measure up to the touch force trackpad found on the 2015 MacBook, but this one is close. I didn't find myself frustrated with its accuracy during testing and, while it could certainly be a little more responsive at times, it's more than satisfactory. The gestures are also useful and can be configured in the settings. You can use multi finger taps to prompt different features and swap between apps. \n\nMicrosoft's Surface Pen has also features some improvements. The body of the pen is thicker and it features a new tip that gives a little more resistance when writing directly on the screen. You can also purchase different tips in a kit, which includes four separate nubs including one similar to the feel of a #2 pencil and another that is more like a fine point pen.\n\nDisplay: What's not to like\n\nYou'll have a difficult time finding a complaint about the display on the Surface Pro 4 because it's absolutely gorgeous. The only downside is that when you look at the display on an outdated or inferior device, it might feel like you're looking through a dirty window. While that might be a bit of an exaggeration, it's just a testament to how nice the display is on the Surface Pro 4. \n\nIt has the specs to back it up with a 12.3 inch, 10-point multi touch PixelSense display boasting a screen resolution of 267 ppi. It's similar in quality to the iPad Pro, which has a slightly larger display size at 12.9-inches, which results in a slightly lower resolution of 264 ppi. However, a Macbook Air, with a resolution of 135 dpi, is no comparison to Surface Pro 4.\n \nPerformance: Plenty of power for work and play\n\nWhile overall performance will depend on the model you choose, the Intel i5 processor and 8GB of RAM were more than enough to get through the day, whether at work or at home. Alternatively, you can go with a 6th Gen Intel Core m3 or i7 processor, instead of the Intel Core i5. Configurations include options from 128GB to 1TB of storage, depending on the processor you choose, and you can get 4GB, 8GB or 16GB of memory. The base model, with the M3 processor starts at $899 and goes up to $1,599 for the highest configuration with an i7 processor, 16GB of RAM and 1TB of storage. \n\nIn testing, the i5 processor with 8GB of memory was more than enough for every day computing tasks, and 4GB might be lacking if you're multi-tasker, keep too many browser tabs running, keep apps going in the background or if you stream content regularly. Also, while it's great Microsoft offers a lower configuration with the M3 processor, it's hard to imagine anyone buying such a high-end device with a mobile processor, but the option exists.\n\nBattery life is impressive, and you'll likely get through an entire day of regular use without a problem, with a little battery life to spare at the end of the day. Microsoft claims you will get nine hours of video play back with one charge, but that doesn't seem realistic in testing. You should expect more like nine to 10 hours of battery with normal usage like Web browsing, using the Office Suite and maybe streaming a few videos or some music. This is more than sufficient if you're out and about without access to a plug to get a charge, or if you would prefer to leave the charging cord at home.\n\nEnterprise-ready? Check\n\nGetting into the enterprise is a goal for most tech companies and Microsoft has the luxury of already being a fixture in the business world. But it's starting to come up against competition, with more Apple devices popping up at work and Samsung introducing enterprise programs. And because enterprises are usually the last to adopt new technology, Microsoft knows it has to keep up its momentum if it wants to entice businesses to adopt the Surface Pro 4.\n\n[ Related Story: Is Apple losing its enterprise tablet edge? ]\n\nEnter the Microsoft Enterprise Initiative, which offers businesses some perks if they want to embrace Windows 10, the Surface Pro 4 and Surface Book. The program allows companies that are already on the Surface users to trade in their old Surface Pro 3s -- as well as other eligible non-Surface devices -- towards the price of a new fleet of Surface Pro 4s or Surface Books. \n\nFor companies worried about security, especially since you can't remove the hard drive from the unibody design of the Surface Pro 4, Microsoft has a fix for that, too. If a device dies and can't be rebooted, Microsoft allows you to destroy the machine on site, and it will ship a new one without requiring you to return the compromised tablet. They've also changed up the warranty plan, since traditionally, each device comes with two warranty claims. Businesses that order a fleet of Surface Pro 4 or Surface Book devices, can group the warranties together to use on any device, without being limited to two warranties per device. \n\nMicrosoft also announced Dell as a reseller of the Surface devices, which means you can get the Surface Pro 4 along with Dell's Hardware Warranty, ProSupport with Accidental Damage Service and Configuration and Deployment services. Microsoft hopes this will give IT departments more reason to get on board with the latest Windows 10 devices, with the support from a familiar enterprise tech company like Dell.\n \nThere are a ton of other built-in security features for both consumers and the enterprise, including Windows Hello, which is actually part of Windows 10 and will work on compatible devices with a camera. Hello will automatically recognize your face, after some configuration, of course, and unlock the device. It works surprisingly well, sometimes I started up the device a good distance away from my face, and it still spotted me and unlocked the Surface.\n \nCan it replace your notebook?\n\nIn the past, I've been hesitant to recommend Surface devices as a notebook-replacement, but the Surface Pro 4 has changed that entirely. The only issue, as with every past device, is the lack of stability when using it on your lap thanks to the kickstand and type cover. If you need to lean forward or shift the device, it does require a little more configuration and attention than a traditional notebook, but it's certainly not significant enough to write this device off as a notebook replacement. The Microsoft Surface Pro 4 is a solid combination of portability, style and performance, and if you decide to use it as your notebook, whether for work or personal use, you won't be disappointed.