I TIG everything. I once borrowed a friends MIG to do some floorboards and I just didn't like it. I have had classes in both and just prefer the quality and look of TIG. Granted, it is harder, but once you get the hang of it stuff usually turns out much nicer.
I would have to say that the time it takes to become a really good MIG welder (beads that look good, proper penetration, wire feed, etc.) is about the same amount of time it takes to become a good TIG welder.
For odd position stuff you just have to learn to push the pedal with your other foot, elbow, knee, ass cheek, shoulder, head, the list goes on. Hell, I have even had other people push the pedal for me in really hard to reach places!