Why are you asking if Chinese dirt bikes are worth buying when you already say you have a Chinese hummer dirt bike. Shouldn't you know if you think it's good or not..since you own it????
Plus, if you can't afford a better brand like Yamaha and Honda then at least you have the Chinese hummer, so why not keep it? It's not like you are going to get much for it if you expect to sell it and buy a Yamaha.
I got a chinese 125 thumpsta becuase i coundnt afford a yamaha like i wanted, Lets just say for the 5 months it lasted i was glad my friend knew how to fix bikes...until it blew and needed a rebuild damn peice of crap
you may as well keep the hummer until it eventually falls apart of dies, in the meantime save for a jap bike, you never know what you can find
Chinese bikes are dirt cheap for a reason, you will end up spending the difference and some on repairing them, most decent bike shops won't repair them either, I would steer well clear of them.
You get what you pay for.
Nothing coming out of China it worth having. First they poison our dogs then it's our kids toys now it's milk products. When are people going to learn.