Here has been my experience: When I bought my 2012 Focus w/ MFT I found it to be incredibly buggy and inconsistently crashing. One thing I found was that most of my issues seemed to be coming from the BT Audio streaming.
Over summer, I too, my trusty iPhone 3GS swimming with me. Needless to say, it was time for an upgrade. I chose to go with a WP7 phone with the mindset of, "hey, it's Microsoft... it will work great with the MFT." Unfortunately, that was not the case. The only function it did pick up was the BT passing my text messages to the MFT. Something that shockingly did not work? Connecting the phone to MFT via USB directly. I got a message saying, "not a recognized USB device." For many, other reasons, I ended up returning the Windows phone and now I'm quite happy with the new iPhone 4S.
One thing I have found that really seems to help with stability is, when I'm running streaming BT audio, I pause/stop the stream when I have arrived at my destination, before turning the key to the off position. I find that it more consistently recognizes the phone as a BT device than just turning it off like normal.
Incidentally, I ran across this article today, indicating that Ford will be sending flash drives to its MFT customers to upgrade their systems.
http://www.huffingtonpost.com/2011/11/07/ford-myford-touch-upgrade_n_1079419.html