If you enjoy stirring things up, try walking into a room of IT professionals and loudly declaring your love or hate for Microsoft Outlook. You're sure to get knees jerking so hard that you'll wish you had stock in arthritis pain creams. However, most complaints and valentines about Outlook are personal anecdotes which, while interesting, may have little relation to reality.

The reality: letting this software behemoth slip into your desktop PCs is like inviting a vampire into your house. Before you know it, everyone and everything's bled dry. Lest you get tempted, read on.

For the opposite point of view, check out my colleague Lynn Greiner's 10 Reasons to Use Microsoft Outlook.

1. Your users don't have infinite time

Outlook has never been the fastest kid on the block, but Outlook 2007 takes a new prize in being extra special slow. When you have large .pst or .ost files (starting officially around 2GB and getting significantly worse as you top 4GB), Outlook happily freezes on you as you work with your mail. You can also run into this problem if you use Outlook 2007 for RSS feeds.

While there's an update that fixes this problem somewhat, some of the recommendations for reducing the trouble are themselves problematic. Who has time to go through and hand purge items from a mailbox that's in the gigabytes? Microsoft also recommends to "Use an online mode profile instead of a cached mode profile." Unfortunately, turning off cached mode increases network traffic, messes with your junk mail filtering, and if you're off the network, good luck with being able to see your mail at all.

There are also issues with using Outlook 2007 to pick up POP3 mail, where Microsoft's handling of the AUTH command is incorrect, causing the POP3 mail checking process to take a painfully long time.

2. You don't like losing your mail

Outlook's .pst files have been notorious for years for becoming corrupted. In older Outlook versions (Outlook 97 through Outlook 2002), if a .pst file reached 2GB in size, the file could spontaneously corrupt itself. This problem became so widespread that a host of companies created products to fix the problem.

For example, there's Disk Doctors Outlook Mail Recovery that can repair .pst files damaged this way, along with fixing other corruption issues and retrieving deleted items (mail, contacts, etc). What are these other corruption issues? Outlook's .pst file can also be corrupted over the network if not stored locally, it can have its header corrupted, or be corrupted while compacting the file to make it use disk space more efficiently. This tool also claims to be able to retrieve .pst files that other tools couldn't because of file fragmentation on the disk.