Originally Posted by
Dunbar
There's a compatibility chart out there somewhere. I've used 5700 and 6700 extensively and there is zero difference in shift quality. The 6700 calipers are slightly better IMO. I think you can get a complete 5700 group set from the online UK shops for <$450. If it were me I'd go with the new 5800 being released shortly or Ultegra 6800 for ~$700 if you need to buy something ASAP.
Yeah, I got my 6700 after they had been out a bit and 5700 had just come out, so there weren't really any OEM or used options and the price was pretty much the same. However, now that Ultegra has gone to 11 you can probably get take-offs or barely used shifters on either one
for a song.