Once you get used to a tablet, it becomes your best buddy for working, Not so much for everything else, it does NOT replace the mouse, you should have both and use them for their respective areas.
Buy a bamboo pen, even the small one can be great if you put some time in it. Many pro illustrators and animators use them and make amazing art with them. You gotta start somewhere.
I've haven't tried any of the new genius tablets, when i bought my wacom genius pens needed batteries to actually work. I suppose they have improved since then.
Of course an intuos or a cintiq are way better, they are the industry standard, but if you go and spend $2000 on a device that you don't know how to use and you don't use it to work, honestly you are not the sharpest tool in the shed. I know many people that do that, just saying...