Just my opinion, but I'd go with a Crimson Trace product.
If you have the 20SF they may Lasergrips for it. That would allow you to mount a Lightguard on it too. That's what I run on my 17. Very effective.
And by the way, nobody -- I mean NOBODY, placed in the night match hosted by CTC without a laser on their gun. It had everything to do with just how hard it is to find night sights in the dark and semi-dark as compared to lasers. Guns with lasers were far faster and more accurate than those with just night sights. And yes my 17 has night sights in case the laser goes down for some reason.
Sendit