I have genius 8x6 I picked up from Newegg.com, was like $85.
The wacom are nice but $$$. Like the others said I don't use it all the time but there are thoose times it comes in really handy.
A few tips,:
if you can afford a Wacom get the wacom, but it will be 2x the price of an off brand.
#1 tip if you get one, and use it in photoshop LEARN YOUR KEYBOARD SHORT CUTS!
learning your short cuts will save you laots of time.