1. It really is fast. TeliaSonera, the Swedish carrier that in 2009 launched the first major commercial long-term evolution (LTE) service, delivered an average downstream speed of 33.4Mbps in informal tests last year. Verizon Wireless, which is using narrower spectrum bands, estimates that even on a fully loaded network, individual subscribers will get between 5Mbps and 12Mbps downstream and about 2Mbps to 5Mbps upstream.\n \n 2. It has less delay. LTE networks have lower latency than earlier cellular systems, so packets are less delayed. This makes a difference when timing is important, such as when using voice over IP, streaming video or working on a virtual desktop. Verizon claims LTE cuts latency in half compared with its 3G network, and says LTE subscribers are seeing latency of about 30 milliseconds.\n \n 3. It could become a worldwide standard. There are only 17 commercial LTE services in the world now, but 173 more carriers are planning to deploy it, the GSM Association says. The WiMax Forum says there are 592 networks using the high-speed Worldwide Interoperability for Microwave Access (WiMax) protocol, but that figure includes both fixed and the mobile versions. Recon Analytics founder Roger Entner compared LTE to the global system for mobile communication (GSM), the cellular standard that swept Europe and Asia while the Americas and South Korea went with code division multiple access (CDMA) networks. \u201cLTE will dominate to an even greater extent than GSM ever did,\u201d Entner says.\n \n 4. The 4G label doesn\u2019t matter. The International Telecommunication Union caused a minor uproar late last year when it declared that neither LTE nor WiMax would qualify as 4G until their next versions, which would bring speeds over 100Mbps. Then it relented, allowing anything that offers a significant speed boost over 3G to use the label. Carriers offering advanced forms of 3G promptly adopted it. \u201cIt has turned into a marketing term,\u201d Entner says. Would-be subscribers should test drive networks and pick the one that\u2019s fastest for them, he says.\n \n 5. It\u2019s not everywhere yet. Depending on how much you travel outside your home city, you may end up using 3G as much as you do LTE, at least for a while. Verizon\u2019s LTE network reaches about 110 million U.S. residents today, which will double by the middle of next year. Its 3G network, which covers about 290 million people, will have greater coverage than the LTE network until some time in 2013, the carrier says. ATaannddT also aims to cover its 3G territory with 4G by 2013. Until then, dual-mode devices will be critical.