<slightly off topic>
It really isn't. Some people say so and quote 'memory bandwidth' as a reason. I've worked in recording studios and even built a digital audio workstation and for the cost of a dual G5 studio mac, you can built a few dual Xeon machines running windows or linux that will easily outperform the mac.A Mac is the best all-around for video and sound. I recomend changing only for this issues...
</off topic>
Anyway...Macs are generally good and well-built computers. It mostly comes down to what software and utilities you need to run. And yes, Microsoft does have a version of Office for Mac.