1 > The first difference is in the way the products are marketed. Roughly: - Bamboo = beginners to intermediate. You get 512 (if my numbers are right) levels of pressure and a few buttons. - Intuos5 = semi-pro to pro. You get 2048 (if my numbers are right) levels of pressure and six to eight buttons, plus a Touch Ring (think iPod ring). - Cintiq = pro. It's the same technology as Intuos4 or Intuos5 (depending on the model), and you get many buttons and one or two Touch Rings depending on the model.
If you can afford it, Intuos5 probably is the better choice if you know you're going to draw a lot on the computer because it allows much more customization (which means the tablet will adapt to your workflow). It's a little more expensive than the Bamboo though - but the price difference is mostly justified. The Cintiq is prohibitively expensive (but otherwise beats any concurrence as far as I'm concerned - I use both Intuos4 and Cintiq technologies).
2 > The human brain is kinda amazing on that regard. You basically look at the monitor and make the gestures on the tablet. One very important thing to pay attention to is the way you place the tablet relative to the monitor - for best results you'll want them to be parallel. It's one less adaptation step for the brain, and that's a lot of performance gain. Also, don't forget that one of the huge advantages of computer drawing is Ctrl + Z - you can always redraw that stroke you failed at getting right the first time.
3 > No, because the professional with a mouse probably knows what he's doing (if he didn't he wouldn't be a professional). On the other hand, there aren't many pros working with a mouse in 2D art at this point from my PoV. The advantage of tablets is just that huge. Tablets are more intuitive than mouses. You'll probably find that learning to paint and draw with a tablet is relatively easy compared to mouse drawing. Also, tablets detect pressure. If you press harder, the line can be more opaque or larger. That simple function doesn't exist on mouses and is by itself enough of a reason to buy a tablet for an artist.
1) intuos 5 specs and reviews: [link] bamboo create specs and reviews: [link] 2) Same way you do with the mouse. Practice. 3) Probably not. "You with a tablet (after learning to use it) will make better digital art than you with a mouse." If you expect a tablet to automatically make you better than another artist then you are probably going to be disappointed. The purpose of a tablet is to allow you to draw and paint more naturally than you can with a mouse.