I've had two glitches with 6.1 so far. Near Shady Sands I had a random encounter with a "weary traveler" who asked me where I was from and what I was up to. I told him I'd learned it was unwise to share that information with strangers, and he confided that he came from Shady Sands. I convinced him to take me to Shady Sands (even though it was very close on the map) but we arrived to a black screen. I think everything was present and working because the music was playing and I could hear the clicks when I pressed the mouse button, but the entire screen was black. Got a save on the weary traveler encounter if you want it.
Second glitch, I had the raider camp go bananas on me when I showed up at night one time (in order to rescue Tandi). All the floating text about the Khans thinking I was a ghost seemed to roll off really, really fast, with no delay (you couldn't read it because it was flickering so fast), and I could run through walls. I started combat and killed everyone, and everything seemed to work okay from that standpoint. In the end I restored the save I made just before I left Junktown (I went there first to pick up Tycho and Dogmeat), and the second time it seemed to work okay. I don't have a save of this because it didn't happen the second time and I'm not at all sure what's going on there anyway. I'll look into it more. Never had this happen with 6.0 or earlier.
EDIT: I've been having the world map crashes too. They're very odd. So far I haven't noticed any pattern to them.
FWIW, I really dig FIXT. If nothing else, it gives me a reason to play F1 again. It reminds me why I prefer the story focus and setting of 1 over 2.