They are completely reliable! Why shouldnt be anyway?
Most famous mobile companies like Nokia, SE etc have their factories in China. Look behind in your cell phone to see the logo "Made in China"!
I have already bought 5 chinese mobile and using that type of chinese mobiles since 2008 and they just ROX.
No problems at all till now plus they have warranty.. Once when my charger cable had a problem they send me a new one with no extra cost at all!
Well to inform you there are many websites that selling chinese mobiles and there is a risk of fraud so you must be careful.
Here was another chinese phone which i have posted here some months ago
http://forum.adrenalinex.co.uk/index.php/topic,438.msg49922.html#msg49922