Well, what do you think?
A decent normal headunit costs $200-300 easily. You're looking for a TV screen (motorized), DVD player, cd player combo for $300.
Of course they are shitty. They are cheaply made with crap parts and you're lucky if it lasts 6 months before crapping all over itself.
Do yourself a favor, save up some money, and buy a decent unit.
This right here is why the electronics market is going to ****. Everybody wants something for nothing, thus forcing companies to start making shittier products that they can sell for less money.