I owned both. The Taurus is fun and the trigger was decent but for the money, I would go for the R8. You can do more with the R8 than the Taurus. When the time comes to sell, the S&W will sell for more and hold more of its value.
While I do not own an M&P R8, I do own the TRR8. I also own a few other variations of the model 327
I can tell you that the 327 family of revolvers is probably the most accurate 357 Magnum revolver design S&W has ever produced. The use of the multi-piece tensioned barrel makes them shoot amazing groups. This is almost an identical design to what made the Dan Wesson revolvers so formidably in Metallic Silhouette competition. The DWs had the additional feature of being user swapable.
There is zero doubt in my mind that I would be willing pay double the price of a Taurus 608 for a Performance Center 327 revolver.
Well this is an S&W forum so you should get most people say "Get the Smith"
Of course comparing a Smith to Taurus on a Taurus forum people in the know most likely would also recommend S&W! The biggest advantage S&W has over a Taurus is quality!
Get the Smith. With that said Smith makes other 8 shot 357's. The R8 is more expensive because of the Scandium frame. You can get one of the stainless 627 variants for less money than the R8. They do cost more than the Taurus but it is an option but I wouldn't be able to pass up an R8 I have one on my wish list.
No question that the S&W is going to be the better of the two guns that you have chosen. If money is a consideration and you intend to keep it long term, the Taurus will serve you well and probably last longer than you will. It's a pretty good weapon but it will never be as respected as the S&W.