you get what you pay for. Intuous has a few more featurers.
The differece is the one between writing with chalk on the sidewalk or drawing on good paper. Quite literally. The Bamboos are pretty much what expensive pro tablets were like 10 years ago, just shrunk down, meaning their resolution is rather crude by comparison, they only support a limited number of pressure levels and no fancies like using pen angles or pen tip rotation. Not saying that this may not work, but it's like trying to draw Mona Lisa on an iPad more or less. If you are seriously into painting naturalisticly and don't just want a tablet as a substitute for a mouse, go with the Intuos line.
The Intous specs are better (higher data rate, more levels of pressure sensitivity, and so on), but if you're going to do digital art and animation, what might interest you more about the Intous is support for things like tilt angle. That would affect your line quality if you use non-round brushes in Photoshop, like flat or oval brushes.