Lots of hand positions, but none that suited me as well as the fewer positions on regular drop bars. So, they really didn't work out well for me. For me hand (and arm, shoulder, neck, and general) comfort results from a relaxed posture more than a variety of hand positions. You may like them though.
I find regular drop bars preferrable. I figure that if I have bent elbows (forearms parrallel to the ground), shoulders relaxed and not hunched, and fingers loosely draped over the bars I can ride on the hoods the large majority of the time. If I want or need to I can use the bends, drops, or straight section of the bars for a break, but a lot of switching up isn't a huge priority for me even with super long days. YMMV.
The only way you will know how they work for you is to give them a try, but I'd suggest that you be sure that you be sure you have a good relaxed posture on the bike first and foremost. A lot of times when folks are looking for more hand positions the real problem is that they are riding with a poor body position and/or a tense upper body. If they exist locked elbows, tense shoulders, and tightly gripping the bars need to be addressed with bike fit and body position first Then think about trying various bar styles if you still want or need to. At that point you may no longer feel the need.
All that said I have considered putting a butterfly bar on my folding bike for reasons specific to that application.
Never seen butterfly bars in carbon, doubt they exist, but I guess it is possible.
Last edited by staehpj1; 09-07-21 at 06:32 AM.