The 12 gal are nice. I have a 12 gal JBJ Nano Cube. I haven't had any problems with it. I haven't been on the boards for a while and I've noticed they have different kinds of nano cubes, almost makes mine look out dated. With the stock lighting you can keep several different types of corral and a couple fish. They are look nice and neat, nothing showing like filters or heaters or anything. Look around and see what you like.
Good luck.