Any advice on a drawing tablet for Photoshop?

I'm looking into a tablet for my spouse, for use with Photoshop CS4 and CS5. I'm wondering if anybody has one or has had one and if it is worth it. I'm looking mainly at the Wacom Bamboo line. I can't drop $200 but $100 or less if possible is great. I wouldn't mind looking into a slightly used one as well. They are an art major in college and Photoshop has been giving them some trouble lately. Hoping this might help for projects. They aren't a pro but they need to use a lot of Adobe apps for assignments. Something mid-range would be great. Or should I go used and get the higher end model?

Also.

We have 3 macs, one runs Snow Leopard and the other two run Lion. Do the tablets work alright with Lion?

This is for a Christmas gift, any other suggestions for gifts will be helpful too. Thanks in advance!