I've had it for almost a year now and I will not be renewing.
Don't bother, go with Google instead for push email/synced contacts/calendar. It's a lot better.
The MobileMe website is crap, the web email is so much worse than Google it's incredibly archaic. If you are on Windows the iDisk only seems to allow you to upload via the web which is also pants.
Better off with a free Dropbox account for 2Gb storage (same as iDisk and implemented way better)
It's a poor service even if it was free, but nope they have the nerve to charge money. Find my iPhone is the only feature other websites can't offer and do better. I don't think it's that useful.
Edit: Heh going free, about time... I've already made the switch to Google and Dropbox for my email/contacts/calendar syncing and file storage though. Much prefer it.