6' on a 17" hardrock.
I've got a 32" true inseam.
The 19" was all up in my junk, plus it felt like I was on a horse.
I took the 80mm stem off and put a 100mm stem on, so now I have the reach of the 19" (60cm) without the clearance issues.
A little bit smaller bike will handle better off road- you can toss it around more.
imo, mtb fit isn't as important as a road bike....you're gettin jostled around, out of the saddle quite a bit etc.....