Since you say you have no experience with a tablet (traditional one) yet, be aware that there is a learning curve. I do a lot of art and graphic design stuff and I very very rarely use my tablet. It always feels like its fucking with my lines, being too sensitive or not sensitive enough. I could draw something the way I want it to look easily on a piece of paper, but it will never come out looking right on a tablet.
I do find it to be useful for very specific lines (long feathery strokes for hair, grass, "swooshes", etc), but beyond that I'm much more comfortable zooming way in and using a mouse.
So, be aware that you could end up feeling the same way before you drop a ton of money on one of these things!
On the flipside, I got to use a Cintiq for a semester in college and it was almost perfect. Worth the slight difference of sliding along a screen rather than having the resistance of paper in the accuracy and amount of time it saved vs scanning in work and redoing the lines with the pen tool.