I have a '97 750 in 21". I'm also 6' and wear 32 slacks. I prefer frames slightly small vs. slightly large, and I like the 21". I do like the ride to be more upright and comfortable...if you like speed and prefer stretched out some, then the 23" might be the right size. These have pretty long stems to begin with...even though I have the 21", I still shortened the effective reach quite a lot with a shorter stem with a fairly long quill.