Sure, the GTS has problems. But it works both ways; When I ask for something, say from the swarms, I get it within five minitues if I offer a Starter. Therefore I don't have to bother with waiting for the right day and all of that.
People get WAAAY too greedy on the gts. It's almost laughable when you see some idiot asking for a lv. 100 mew for a starly. It's also unbelievably frustrating since they make it harder to find honest trades