Skunk,
I went through a S&W Academy course with a Colt Combat Commander in a Don Hune JIT ("Just In Time") No. 10 belt slide -- it's very similar to the Yaqui (I used a Galco leather mag. carrier in the class; still do for CCW).
I also have a Blade Tech Kydex OWB for a 1911/Para. that fits a Govt. Model and, of course, the slightly shorter Commander.
Get the kydex, for the following reasons:
1) See my post under "gear" about losing my S&W 19 yesterday on a public playground. It slipped out of the belt slide holster and fell to the ground as I was on some equipment with my daughter. It was suggested on the thread that I get a holster with a thumbbreak, which I canot stand. Too slow.
2) The Kydex fits the 1911 better and has TWO tension adjustment screws. Good for acrobatic stuff.
3) The Kydex is very, very fast, esp. with Blade Tech's front cut out.
4) The Kydex will protect the muzzle and slide, unlike the JIT, which lets the pistol bump on all sorts of things: office desks, store displays, etc.
5) It's silent. Leather can squeak; Kydex doesn't. And Kydex doesn't absorp sweat.
6) Weight difference is imperceptible in my hand.
The Yaqui slide or similar isn't bad, I just feel Kydex is better. FWIW.