I haven't used those but I absolutely love my R.E.D s ones and also have the Protec IPS Rail guards. I like the R.E.D s ones a lot better because they have a seperate knee and shin guard. I am assuming the Protec ones would be compareable as well though I have no experience with them. I don't think I like the idea of the big ass straps wrapping around. The R.E.D. ones have velcro straps, but they are lower profile.
I ordered the R.E.D ones from Dogfunk and after trying them on, I packed them back up and sent them back the next morning. I don't have huge calves but I do play basketball and even with the Large size I had trouble fitting and that stretchy stuff sucks.
I called around different moto cross and mtn bike shops and found these ones for $12.95... a hell of lot cheaper and better fitting too.
Not bashing you homie, but those R.E.D's suck big time!
Cycle Gear - SHIFT 2007 Knee/Shin Guards BLACK: 2007 Knee/Shin Guards, BLACK