Had an Aiptek 6x8 tablet - liked it. Worked just fine - though the battery did need replacing which took me a minute to figure out when it stopped working.

Got an Intuos 3 6x8 - LOVE it! Well worth the price for professional work I think - and I just can't seem to make a 4x5 work for me before anyone says anything about my size choice. Tried over at a friend's house - didn't like the small size. The big-mamma-jamma one was just too, well, big! 6x8 seems just right. The 4 programmable buttons at each corner and the slider (for zooming in and out) keep my hands off the keyboard (mostly - still need keystroke shortcuts) and focused on the work.

Got the Grapphire 4 6x8 (silver) for my 2nd computer and I love it -can't figure out the difference as to WHY I love it vs the Aiptek but there's something just better in the feel, and working with it. Also doesn't hurt that the pen doesn't use a battery either.
Good luck-
-Lew ;-)