Just picked one up a few weeks ago and really like the way it shoots. Very well balanced, heavy enough to help with recoil and the sight picture with the fiber optic that came on mine. I've only has S&W .357s to this point. Although the trigger on the GP100 isn't quite as smooth, I really do like this gun. It's built like a tank!
Ruger revolvers are the best. Heavy duty and built well. There are aftermarket stuff if the trigger needs cleaned up. Don't be afraid. If buying used check timing, forcing cone, bore, try to get a round count. Do your homework like anything else.
Can easily ring the gong at 150yrds and take a milk jug of water off a fence post at that distance with a 6" GP.
Don't forget to factor in A) shipping and B) Transfer price.
The price itself on the site is a very good price, but chances are good that you'll pay ~$50 more than that to have it in your hands. Give a local shop a chance to price one out for you.
HOWEVER - those rosewood grips aren't being offered on all models - and seem to be a distributor exclusive. That may be worth the extra costs / hoops involved in ordering one online.
ETA: I read further - that's a police trade-in revolver. Just be aware of that. If I were in the market for one, and had the money, I'd likely jump on it myself. I had a 4" blued GP100 w/ rosewood grips at one time. I sold it for some stupid reason. (but I like my 686 way better now, though. heh)
I've got a 4" Target Gray Ruger GP100, and it's one gun that I will never get rid of. Very accurate, and built like a tank. Buy with confidence, Ruger revolvers are built to last.
The recent Ruger GP100 triggers feel better to me than the recent S&W. I had been shopping around for one & several vendors at the last Indy 1500 agreed. I lucked into a stainless 6" "used but never fired new in the box" for an amazing low price. It even had two grips. It shoots fantastic.
I had a 6" stainless, really liked it, traded it off, then missed it and bought another. They are solid, durable and accurate. You will not regret the purchase.
Every Ruger GP that I have shot or worked on is more accurate than 90% of the owners. My wife shot USPSA/steel with a GP for years and that thing was a tackdriver (and she beat a lot of guys with it including me a couple of times). All Ruger GPs could benefit from some action tuning - they're kind of rough out of the box but they are great revolvers for the price and Ruger stands behind their products very well.