I just picked up the Wavemaster and I have seen an 8 degree reduction at full load. I was running at 55-56 celcius case temp, but now it is rare I see more than 47. With the sides of the case off, I won't go above 44-45. (How do you make the degree symbol, btw?)
I was using a cheap generic case with one fan, though, so some improvement was virtually guaranteed.
Still, the Wavemaster has its flaws - the installation of the CD-Roms was irritating as all heck, as Coolermaster did not machine any "guides" for the drives into the frame - you're forced to hold the drive up as you screw it in. The door can get a little annoying, but I'm not one to constantly switich CDs or Floppy disks. If I was, I would have pulled the door off on day 1. The case itself is a bit longer and taller than your regular mid-tower, so if you have limited space on your desk or countertop, this could be an issue. These are all small details, however. The case has no major problems IMHO.
The case looks great and does not make a lot of noise. That's my opinion, though - some people might be more sensitive to that sort of thing. The aluminum is rock solid and I do not think this would break easily.
I don't have any airflow problems, though Antec does come with better stock fans. Basically, all I need now is an Artic Cooler on my 9800 Pro and I suspect I'll be dropping into the high 30's for overall case temperature.