I have to say this MM experience has been very unApple-like. Below are the problems I have had since signing up for the free trial.
1) Calendar sync - I set up my account on my MBP and synced calendars to MM, no problem until...I then go to my work iMac and try to merge that calendar to the existing one...and erased the initial calendar in the process (yes I hit Merge Calender upon prompt). This erased all the iCal data on my iPhone as well. Luckily my MBP hadn't synced yet so I quickly overrode the MM calendar, data saved, but just...
2) Contact sync - see above, except this time for Contact data
3) Here's the worst IMO - somehow, as someone mentioned above, my iPhone and Mail ended up with TWO MM email accounts - one empty with no mail and the other full of mail I had transferred from another account (doing this for the push mail from MM). On closer inspection, the account with mail in it was tagged at me.com, while the empty one was mac.com (?!). I never had .mac service by the way. Now here's where it gets weird. I go to my iPhone to disable the push services from the .mac account figuring it was useless and some kind of goof. Disabled mail, calender, contact, etc. I then go to mail, ok emails are still there. I then go to calendar, empty!, contacts empty! Apparently my iPhone was syncing mail through the me.com account and the calendar and contact info through the mac.com! I had to erase both accounts on both computers and start all over.
4) I enabled time zone support for Chicago on MM (already had it for my iCals). I then sent an email, a real email to a colleague, that was labelled as having been sent at 6AM (it was 8AM CST). I went back to my MM account, time zone support said Chicago, I shut off and turned back on time zone support, selected Chicago again. Send a test email - again 2 hours earlier than reality. After performing the above mentioned resetting of my account, things worked fine, but still that was weird.
All in all it took me about 2 days to get everything straightened out - unacceptable. Right now everything works okay with the major exception that push services are not occurring consistently. I tried these out (mail, calendar, contacts) after getting everything in order, and they all seemed to be working as advertised, data moving from computers to cloud to iPhone and vice versa. Now I am noticing my email is not always getting pushed to my iPhone. Right now I just added a new iCal event to my MBP and did the manual sync to move the data to cloud to iPhone. I'm looking at my iPhone cal and the event is not there. I manually synced the MBP again...still not there.
This is very frustrating and I'm kind of just venting, but these failures are hard to comprehend. I already get push email from my ATT Yahoo! account, the only reason I tried MM was to be able to sync calendar and contact info between 2 Macs and an iPhone, which I was doing manually before and was a major pain. Without reliable syncing for calendar and contacts, I don't want to give Apple my $99. Back to my Mac and iDisk are nice but not a necessity for me. Well, now I have another 60 days on top of the existing trial period (54 days) to see if they can get this to work. If not, I won't be signing up.