I have not any real problems in the year plus I had the MT. The original firmware was terrible compared to the latest, but for the most part the last few firmware's were fixing small things.
It is important to find a CF card that the MT likes, and there are threads on that, and I always record at 16 bit, since that is how I play the file too, so I don't really have the 2gb filesplit issue.
I have used the deck as a bit bucket and as a stealth recorder, and found both ways fine. I have not lost any recordings, but of course I have missed a few seconds of the beginning of a show here and there...
Currently I am back to just using the MT as a stealth recorder. I do slap on a battery pack, because I have a 5gb microdrive and it eats power. At some point I'll change when I find a good reliable 4gb card that is cheap. I also recently added the SP powered battery box that snaps right on top of the MT, I like that a lot too, it takes up much less room than my home made 1/4trs>1/8 dongle. I recently got a Tascam HD P2,for wide open recording and that is simpler than using the MT along with a UA-5 which I used for many months with no problems at all and great results.
I don't think you can get anything better for stealth or portability. That deck is amazing for it's size, and whether with the t-mic or a little better set of small mics, it is fantastic, a whole world away from the cassette shows I made in the last 3 decades.