For my .02 cents worth. I bought based on filtering quality first. I think the CAI is the best looking intake I've seen and has great quality components, and in all fairness didn't find alot of filtering info on the CAI brand, but I was shooting for a stock look anyway and trying to get the best air filtering possible while still enjoying the other benefits of a cold air intake.
I opt'd for the Volant Cold Air Intake with the Dry Powercore Donaldson filter. You can get one for under $250 and the filter is good for 50-100k miles. You can blow them out to clean or replace for $80. They have great filtering and can hold alot of dirt without restriction. See here -
http://www.donaldson.com/en/engine/s...ary/059806.pdf
Photo -
http://www.phastekperformance.com/20...cal-415036.htm
In my opinion, I wouldn't buy cheap, and I would research. If it's a bit pricey, just wait and save for it. Put good parts on a $30k plus car.