Are more expensive chains also often made with harder materials than the super cheap ones? I've read that, but don't know for sure if it's true or not. If so, the super cheap ones would wear out faster.
My $30 SRAM chain on one bike does seem to be a little better than the cheapo $10 chain on another bike, but they're different bikes, so maybe it's not all the chain. Both have regular Shimano cassettes of comparable quality, though, so maybe it's the chain. I should try the SRAM on the other bike one day and see if it's any different.