My MTB conversion is (or was, I haven't looked at it carefully yet) one of the more fun bikes I've had. The key is figuring out the brakes...cantis give lots of options, but generally are pickier than v brakes. V brakes limit lever options, and thus shifting. If I had everything perfect, I'd probably go disc with brifters. I went with vbrakes, tektro levers and suntour commands. I'm not thrilled with the shifting, but the rest is fantastic.

The other issue is stem...you need something VERY high and short.