Originally Posted by
TANC
Have both and can't tell the difference. Go with new. New 105 is just as good as older ultegra anyways.
Same here. I currently have one road bike with a 105 group (5700) and one with an Ultegra group (6700) and I don't really notice any difference at all when riding, and both bikes were upgraded from versions (5500 & 6500) that worked the same as well. To be honest, the 9-speed groups have 9 speeds and the 10-speed groups have 10 speeds, and the 5700 105 parts are black, but other than that.....
I'd probably go for the new 105 group though, because then I don't have to deal with any potential mishandling/abuse by previous mechanics or riders.
Ride Safe!