Let's not turn this into a mac vs. pc thread. If truth be told, both OS are not true realtime OS which is required for proper audio recording and reproduction. If there ever was a true multimedia OS, it should have been BeOS.
I have access to both win machines and mac in the office. Windows machines will have stability issues if they are not properly configured and have parts carefully chosen for compatibility. Some of our 'sampler' pcs have been working for years without issue, with hardware failure being the only fault encountered. Macs have similar problems with hardware, becoming unstable when drives or power supplies exhibit impending failure. What I hate about MacOS is that you can't tweak it for better performance, and it assumes that their drives do not need defragmentation at all.