If you're contemplating switching to another e-mail provider, but have been too lazy to do a feature comparison of the competition, there's a new tool that might be of assistance. Aptly named E-mail Service Guide takes more than 100 hosted e-mail providers, and lets you comparison shop by feature.
This is handled gracefully with a search tool that lets you plug in which options you want, like whether the service has POP3 and IMAP (Internet Mail Access Protocol) support, or customer service by phone or e-mail so you can talk to an actual human if something goes wrong.
It can also tell you how much each service will cost, by breaking down its price according to how many months you're planning to use it. This includes things from the fine print like sign-up fees or required contracts, all of which can be simply sorted by column.
Since the tool is focused on premium services, missing are consumer-grade options like the vanilla version of Gmail, Windows Live Hotmail, and Yahoo Mail. Instead you have providers like Zimbra, GoDaddy, and Rackspace--many of which have service license agreements, multi-user seating, and more generous attachment size limits.
See also: Wikipedia's chart of Web mail providers