What is the Yaqui slide holster best for..Quick draw?
Does anyone prefer the Yaqui?

It's for clearing your gun of the holster more quickly than with a conventional holster that covers more of the gun and barrel.

George

Gotta disagree w/ya' on this one George. The top of the holster is about the same as any other holster. You won't "clear leather" any quicker with a Yaqui design.

I think of it as a "minimalist" design, just enough leather/plastic to hold the pistol in place.

I've got a plastic one that came w/an XD. I don't like it as my XD seems to be "top heavy" when carried in this holster. Conceals/feels just fine in a regular Fobus holster.

Might be a better option for single stacks and revolvers though?

Also exposes the end of the barrel/front sight to view if not careful!

Not to fond of OWB holsters except for USPSA/IPSC

I have never been a fan of the Yaqui slide, or any holster that leaves a lot of the handgun exposed. I wonder "why"?

Why have the gun exposed to damage, dust, and weather???

The best low profile belt carry, IMHO is the Milt Sparks "Summer Special" style of IWB holster.
For best comfort you should buy your pants 2" bigger in the waist.
Also when buying a suit, be fitted for the suit, pants and coat, with the gun and extra mags in place.

I have never been "spotted" carrying using a Milt Sparks Summer Special, even in the summer with just my shirt outside my pants, ie not tucked in.

I have the Sparks summer special and that's an excellent carry holster.
I have a TheWilderness Zip-Slide which is a Yaqui type but of plastic reinforced nylon.This type of holster must be very well made and perfectly fit the gun.Otherwise it won't work well.Yes you may bump up the gun though a well made one minimizes that problem.I've used mine for many an IPSC match and it's my carry holster for my P7.