I’ve only played with Sebastian, B’s MacBook Pro, for a few hours while getting it configured for B, but from what I’ve seen I really like it.
For the past several years I’ve been running Linux both on my desktop and my laptop. The recent move from RHEL to Fedora on both systems helped with the usability issues but it’s obvious to me that Linux still doesn’t have the spit-and-polish that end-users expect on a desktop workstation. Still, I’m much more productive on a unix-based system than I ever was on a Windows-based system even with cygwin installed.
OS X seems to have the best of both worlds: a unix system with a very polished desktop environment. Moreover Apple isn’t trying to hide the unix underpinnings either — you can easily run a bash/ksh/perl/etc script from the Automator. A real scripting language built right into the OS — no more learning VB scripts just to automate some of B’s tasks! [Aside: powershell might address some of this gripe for Windows systems, and I’ve heard great things about it, but it’s been a long time coming.]
While out at a customer site last week two of the IBMers out on-site were using Macs. When my laptop comes due for an upgrade in ~1.5 years rest assured I’ll be moving to a Mac either on IBM’s dime or my own.