That's why we are recommending others like interways.net
They have Push sync for mail, contacts, calendar, online files, complete Apple integration AND complete Windows integration. They can even sync different computers and systems. It's completely integrated into the Apple ecosystem!
And it has all the calendaring features for professionals, as well: Sharing, multiple calendars, subscribing to external calendars and pushing them to the iPhone, etc. You don't get that with mobile me. Just give them a try, I was amazed myself. Checking them out won't cost you a thing...
And they are a specialised mail provider for quite some time now (quoting their site), so terrible things like mobile me losing mails should not happen there.
They are much more open than Apple's thing, supporting most devices, even BlackBerries, Windows Mobile, all Apple devices, even Linux, etc.
So why stick with mobile me (expensive, slow, no real desktop push, losing mails, ...) when you can get it right someplace else?
BTW: They have a free trial month, no obligation, no credit card details before signup,...
Well, you see, I really like the service.