I would agree that Vista is probably a little too restrictive for using as a pen testing platform. I 'downgrade' all my Vista boxes to XP. But as for Mac not being a good platform, I would have to disagree. I use mine for a great deal of tasks (active exploitation, scanning, etc..) during an engagement. I personally don't have a preference and will use whatever platform gets the job done.
I've seen a few posts recently that state that you cannot do packet injection over wireless on Windows. This is incorrect.
http://www.cacetech.com/products/airpcap-tx.htmAirPcap Tx (and AirPcap Ex) can inject any kind of frame, including control, management, and data frames. These frames can be transmitted at any allowable rate depending upon your adapter.
http://airdump.net/papers/packet-injection-windowsObviously injection is also dependent on your wireless NIC but it is doable on Windows.
dean