Beware also of the frame rusting from the inside. I know of a nasty accident when the frame just disintegrated when the bike hit a bump. A good point in favor of the Treks, as their frames are aluminum.
There aren't decent chains available here. In Britain you can get nickel-plated rustless chains (made in Germany I think) at a fraction of the cost of stainless steel ones, but I've never heard of them here.
But none of this matters for a bike used in a more user-friendly environment. The main problem there with the Chinese bikes is that the metal is low grade and soft, so wears quickly.