Wow, I'm surprised Re-bout lasted so long before getting canned. It's not like most of the US ever cared about KOF '94 back in 1994, much less a shinier version that feels like a mid-90s fighter twelve years later. I pretty much agree with the comment that those who would enjoy it are probably people who have already imported it anyway. I've had it since the December 2004 Japanese PS2 release. I like it a lot, but then again I paid over $100 for a used Neo Geo cart of the game back in '95 or so. I'm not exactly most US gamers. The prettied up levels are done well, I guess. Lots of cameos and detailed 3D backgrounds. The thrill soon fades from that though, and I tend to play it in "original" mode (which allows you to play in the original stages with updated smoother graphics and retouched 2D backgrounds). It also does contain a perfect version of the arcade/Neo original. If you don't like the gameplay of the original though, you won't find it terribly enhanced here. It's rather stiff, the AI is mid-90s SNK through and through, and it does feel less polished than more modern 2D fighters.
Neowave? It's a good deal for $20. If there are enough people online it could be a satisfying online game. I personally care a little less now, since I've been playing Neowave on PS2 since last summer and I've moved on to NGBC and SS Tenkaichi. Still, a good game. I think it plays great - feels a lot smoother than 2002, has a great soundtrack, and looks nice. I never was that into 2002, but I like Neowave. If you haven't played it, it's certainly worth $20 (or $30 for that matter).