A good friend of mine owns a Leica R series camera. I don't remember which one but it is earlier than the R8. My daughter owns an Olympus OM-1. Both are nice cameras but I much preferred the Leica for the way it felt in my hands. This of course is just my preference.
If you really like the R8 then go for it. If you are looking to greatly improve your image quality then I would look for a medium format camera.