Here's another variable for the mix. A lot of people use flat bars and upright geometry bikes for a variety of reasons, ranging from preference to medical. However, many of those people while preferring the geometry are less than happy with the hands after a while. (You can do a search and come up with lots of threads about this.)
So. For another (and hopefully final) variable in this fray, I'd like to offer this thought, which has also been widely discussed in many of those same threads.


Currently $9.95 at nashbar. Another $15 for some good squishy bar tape, and you're set!

Do a search on butterfly bars, and you'll see all sorts of unique setups on this message board. I have these on my ATB as well.