I was dissapointed with 5. So I still use 4. It's great and everything but the RSE was a big let down for me. It really does sound like crap. I have played around with it and tried the different guitar sounds, played with volume levels etc, but I am just not happy with it. When I play along to guitar pro tabs I play through my line 6 hooked up to my PC, through my PC speakers and it just sounds like crap trying to play along with a mushy rhythm guitar. I would say buy 5 and if you don't like the Realistic Sound Engine just turn it off, because 5 does have much better features/layout/appearance.