Yep. The most recommended brand is Wacom. I'm using a 12x9 iBall tablet though, & don't feel like I'm missing out on anything really. I'm not sure of Genius though.
Regarding the feel of the tablet as a drawing tool, I think your mileage can vary depending on the actual size of tablet coupled with what sizes you are used to when drawing on paper. The smaller tablets will require short strokes for greater travel on-screen, at 100% zoom. Of course when you zoom in, that changes.
This probably won't matter much, since you will be partly re-learning drawing, given that you're essentially viewing the screen while drawing as opposed to watching the lines develop under your pencil, as you draw on paper.
But if you do err on the side of a bigger tablet, there is also the option of setting up the software to use only a certain part of the tablet. So in a way, that is a safer bet.
It's best to get a demo of the tablet, if possible. Just try & get a hold of the stores selling wacom, through their website. IIRC, they have a few stores which demo products mentioned on the site itself.
& before you do demo the product, it's best to learn about the pressure sensitivity options in Photoshop, so you can try that out. For instance, changing the width of the brush stroke or opacity based on the pressure.
I think if you're a lot more specific about what kind of work you intend on doing, you'll get a better response. HTH.
