I've switched. Still transitioning data, sorting out applications and learning my way around. Most of my hardware has been compatible, just a few more things to try out. I've got XP running via Parallels for a handful of programs that don't have Mac equivalents, or at least with all the functionality I want, particularly Family Historian, which is brilliant.
One of the reasons I switched is summed up here. I just can't be bothered wasting my mental energy supporting Microsoft's price differentiation strategies. And the fact the UK editions cost almost double the US price ('cos changing $ to £ is *really* difficult). And I have just had enough of rebuilding machines every year as XP grinds to a halt. Rebuilding Tam's laptop was probably the final straw.
Yeah, maybe OSX will have it's own warts, but it's getting it's chance. At least, until Linux has decent colour management.