Fond memories. I used to use WindowMaker on my old RH 6.2 system (or was it 7?), maybe even Fedora 1. But I never understood the dock - I was expecting a Windows-style task bar and the dock really isn't that.
The fact that it sat beneath other windows meant you had to constantly shift windows to get to it, which I found frustrating. Likely a configuration option?
It probably runs excellently on modern hardware, albeit with no GPU acceleration or anything to reduce main CPU cycles.