Nothing wrong with them. You may find things harder to adjust, or unable to adjust, materials will be cheaper, things may simply not work as well as with a higher-dollar item.
It's all in what you want to do. Personally, I think you'd be better suited to getting a cheaper brand-name tool (Ryobi, Black & Decker, etc) than going with something that is only made to be cheap, and I wouldn't recommend you EVER buy a cheap power tool, but I'm learning that to some folks, cost IS the main factor. Ease of use is secondary....until they get it home and call me up asking how it works and why doesn't such and such fit and blah blah blah.