I just got back from Guitar Center, and am now the proud owner of a GK 400RBIV. They just got them in today. They are selling them for $489 just like everyone else, while I believe the 400RBIII is still $420. I got mine for $469 though. As far as I'm concerned, the extra price is worth it. I've been playing it a bit through my Avatar B115H and Lakland 55-01, and this thing sounds really good. It sounds warmer and has more punch than the 400RBIII. It looks much better too. I had a thread a while ago about a problem I had with the 400RBIII making the Avatar fart. I'm beginning to think the problem is something else now. The same thing happens with the 400RBIV, but not until a much louder volume, and it isn't nearly as bad as the 400RBIII. When I tried the 400RBIV at the store, I had it cranked through a SWR 15 and was using a Stingray 5. There was absolutely no farting at all. So I think it might be my cab or bass. I'll have to try and find out again at my next practice. The new GK's are out though, finally. And me thinks they are good.