Yeah, stick with Wacom, even if that means buying a smaller tablet. A5 tablets are quite cheap, but you probably want an A4 one. I would scour eBay for a Bamboo or something a bit bigger if you can afford it.
The cheaper, budget tablets do an ok job - the problem I found is that when it comes to a graphics tablet, OK is actually pretty terrible. You want something more from the tablet, more organic and natural work, more detail (half of it by accident sometimes) - well you could spend $80 on a budget A4 tablet, then kick yourself for not getting a Wacom regardless of price.
I've had a few budget tablets in the past, and they all break my heart eventually. I want a tablet for my Mac, so I'm thinking about a Bamboo, but definitely Wacom, I won't even bother looking at other manufacturers.