JW,
Obviously price is the biggest issue, but also, if it has some kind of intergrated splitter/airdam, that would be good too.....I like the look of the Showcars units (with maybe a little more agressive splitter), and would have bought one of those if the quality and fit was better.
I do concede that you will have to appeal to the majority here, but just my 2c worth of preference!
Tim