The linux version is quite nice. I think many people will have problems dealing with OpenGL drives. It lagged quite a bit because Linux often uses the mesa (software rendering) by deafult. Once I installed the video drivers (ati uses the fglrx set) we were good
There were problems with 3D servers, and running it via command-line it was because the snowman and some other things were not in folder config. Once I updated the folder config it downloaded a
lot more things. Problem went after it started loading and rendering grass, kept getting a segmentation fault on Mushia. Also I played UN for a bit, but after I played for a bit I couldn't even log on player because it would segmentation fault on me and it'd close (last thing in log was loading map unmap.txt). I think the problem might have been due to missing car_Idle.gani file. It seems Linux (and I'm assuming mac as well) versions encounter problems with missing files (as I found on nearly all servers they called for cached files or so that weren't actually on the server).