I remember I have tested their "service". It was so buggy, that I had no intention to pay them. Out of the top of my head:
- the order of contact groups was really messed up (not alphabetical, no order)
- some calendars were not updating unless the page was refreshed manually
- the problem with growing outlook file (MobileMe was corrupting the database in some way)
- problem with 1 day shift of birthdays
And I was testing different ways of syncing (from desktop and from...