A lot of people have been writing about problems they've been having with MobileMe, Apple's recent replacement for .Mac, to the point that I can't actually think of any good things that I've heard about it. Steve Jobs is even on record as saying that it's not up to Apple snuff.
Thus far I've been silent on the issue, mainly because thus far I haven't had any problems. That, however, has changed. About two days ago, my calendars stopped syncing. Changes I make in iCal are no longer reflected on the me.com web calendar, nor do they get pushed to my iPhone. This is rather a large problem, as it means I have no access to my calendar when away from my desk, which I am most of the time. To make matters worse, me.com claims to be incompatible with Firefox 3.0.1, at least when I visit from my Gentoo Linux powered ThinkPad which means that even if it was syncing, I wouldn't be able to access my calendar from it and would be restricted to just my iPhone. I'm sure that a little messing around would result in it working in some browser, whether it's Firefox inaccurately reporting its version, or a WebKit based browser claiming to be Safari.
This is rather a large problem for me, as it basically means that I have little to no ability to view or manage my calendar when not at home despite paying not only for MobileMe, but for an iPhone, the one device you'd expect to not have compatibility problems. This may be enough to make me switch to using Google calendar, despite the fact that it won't sync with iCal or my built-in iPhone calendar app, which I vastly prefer to a web-based interface.