I've bought a couple of different cheek rests over the years. The problem with stock packs is that most are not adjustable. Once they are on the comb, they rarely are the right height for my eye - either too high, or still a little low.
I've gone the Kydex route as well on a couple of tupperware stocks. Pretty good rest, but the thought of drilling holes in some of my nicer stocks (wood & carbon) left me still looking for other solutions.
I finally stumbled onto the Bradley. I can move it from rifle to rifle with ease. No drilling and yet it feels very secure. Not only is it adjustable for height, but you can actually build some offset into the cheek rest as well. Price was a little hard to swallow, but in the end - I came away with the best answer for me.