Overall - I favor no strap - I do not want anything that will impede the draw, tho I know folks with them reckon to be pretty slick breaking free. (I have a couple of rigs with straps - one is for the R9 - a belt slide.)
I do as a result want a rig where I can all but do a handstand (ha - used to - no more since arm got bust) ... and it stays put.
There are those who want the piece to be harder for a BG to wrestle into his possession - valid point but - for me, I would hope sufficient situational awareness would have me at very least with hand close, if not on gun.
So - your choices?