I love my Uncle Mike's holster.. it's plain & simple. I have never understood that "upper strap" thing, it just doesn't work for me..
I carry a 9mm Baby Glock, or a S&W 38spl snubby, both in ankle holsters.
The only issue I would be aware of is: Get the SMALLEST, LIGHTEST, LOWEST PROFILE weapon you can control, even 20 ounces on your ankle all day takes some getting used to.
I tried the Galco, very comfy, very expensive, but it made the Glock stick out farther than the Uncle Mike's.