I signed up for the trial in late august.
I was extremely dissatisfied. They sold me on that "over the air" syncing bit, and I thought I could really use it, but in the end, it never ever worked. I think I managed to get my contacts to sync up to the web, but Mail never did. Calendars would sync from the iPhone up to the web every so often, but not on any sort of predictable means.
Here's what I want: Whatever's on the iPhone to be up to date with whatever's on the computer. That's all. If I read a mail on the iPhone, it better get read on the computer as well -- even using POP. I want my family/business to all have a common calendar, that all of our iPhones automatically show new events on, that anyone can add to. Never worked.
If my iPhone's on the same wifi as my computer, there should be some air syncing of this kind of stuff, automatically and transparently.
But, even with the cable, I make due. It works pretty well with a copper connection.
MobileMe? Forget it.