Learning to use MAC takes a few minutes to read thru the manual and guide
- to learn some of the basic short cut keys (or usage of the super Macbook's touchpad)

Getting used to it depends on how often you used it. "Apple" key is sort of like "Ctrl". Ctrl-C for copy becomes "Apple-C"
- this takes some time to get used to... as i often switch between OSX and Windoze, i still always use "Ctrl" ......

Talking about visual fanciness, i don't think that Vista is way ahead. OSX looks great in a much more .. erm... simple and elegant way.

Programs Availability...
Well, it might be some problem to certain groups, but there are always "replacement" for the OSX. e.g i am using NeoOffice instead of Microsoft Office