I always do groundwork with my mare in a rope halter, and occasionally go for trail rides in it. I prefer my bitless if I plan to do a bit more just because it gives clearer directions than having the leadrope tied into the chinknot. I really dislike flat halters because she leans into them and they have no feel.
"Are you one of those natural horsemanship nutjobs?"
- so true. The minute I start talking about how I use rope halters and bitless bridles, people give me 'that look'. Try explaining to them why you keep your horse outside all the time and don't put shoes on.