Yeah, if your going to shoot it a lot go with a 627, The steel frame really helps soak up the recoil. If your going to carry it more than shooting then the R8 is nice.
Both is always an option. 627 PC top, and a TRR8 bottom, MOOONCLIP RULE!
As for holsters any N-frame holster for a 5 inch barrel length should work assuming you don't have anything hanging on the rail. I use the same Blade Tech holster for my 625, 627, and TRR8