As an iPhone user, that iOS sync is a big deal for me; I've found few other programs that can do this. (Android users have it easier, as they can sync their contacts and calendars with Google's Web-based services.)

So what's the problem with EssentialPIM Pro? Not the price: It's quite reasonable at $39.95. But it's a bit weak on the email front, lacking a global-inbox option for multiple accounts and a right-hand reading pane for messages. Plus, it doesn't mark a message as read when you reply to or forward it -- a ridiculous oversight that inexplicably plagues other mail clients as well.

In fact, that's one of my only complaints with (free for personal use, $49.95 for Pro), which runs EssentialPIM a very close second. It makes simple work of importing data from Outlook (among other sources), though it doesn't actually sync with the program. And it suffers from that irksome reply/forward problem.

Even so, eM Client is arguably the most modern and compelling Outlook alternative available today. It's particularly good at integrating with Webmail services like Gmail, Hotmail, and Yahoo, and it supports multiple calendars (both local and cloud). It also supports instant messaging via services like Facebook and GTalk, and the clever Sidebar pulls contact details from Facebook when available.

Perhaps best of all, it offers contact, calendar, and task sync with Android, BlackBerry, iOS, and Windows Mobile devices, though this comes courtesy of the optional Sync2eM service. (The developer offers a free 60-day trial; I couldn't find any information on pricing after that.)