We use Macs here at my work place all running OSX (about 90 or so G5's) let me say I am GLAD to be a Windows user. We have about 300 PC's running Windows XP vs 90 G5's running OSX. The Macs account for about 40% of our workload, which is pretty bad considering the marginal number differences.
Now all our die hard Mac fans think its normal to reboot evey hour
So I will listen to them tell me how much better they are than MS. Now these things just suck on a network. Not sure if its the mix of MS/Mac, but gosh I have seen that "rainbow beachball spinning wheeel" thing so much it makes me want to vomit. We are in the process of implementing an Xserve so we will see if that helps at all.