Hmm...
I think that it's design features are the best out of any revolver on the market, but since the fit and finish is spotty and the triggers can be a bit iffy, I would say that it would be hard to justify that they are the best. I would choose a GP100 over anything else, but a lot of other folks wouldn't.
Now, if you are talking about their new match model, I will agree with you 100%. Superior strength, great fit and finish, and a great trigger out of the box. I would take this handgun over anything else, including autoloaders. I sold off my revolvers a few years ago, but plan on getting back into them because of this model. Heck, even Jeff Quinn said that the new Ruger match model is his new favorite double action revolver.
The person that said that there are not enough grip choices for a GP100 is wrong. With the grip peg, you can customize the grips, on GP100, more than any other "medium-sized" revolver. You can use full-sized grip from almost all grip manufacturers. You can even use the grips designed for the "large" Super Redhawks, which are essentially hogues with extra padding to tame recoil. You can also use compact-sized grips, if you can still find them. I used to have the old compact grips (with the wood inserts), rubber hogues, and the old-style grips with the wood inserts.