I bought this a little over a year ago and it's still holding up my iPhone today. The only problem I had was the lower hinges that holds the phone (or other devices) up cracked. A little super glue helped keep it in place.
I used a gift certificate, so I really didn't "pay" $30.
There's another product that looks exactly like this by Bracketron that is currently selling for half of this:
http://www.amazon.com/Bracketron-UCH-101-BL-Universal-Holder-Mount/dp/B001UGMTKC/ref=sr_1_10?ie=UTF8&s=automotive&qid=1279276177&sr=8-10
As a consumer, I look for the best deals. And I look out for my fellow consumers.
I highly recommend the cup-holder style holder over the vent or dashboard mount if you have enough space (i.e. SUVs and vans) for it. Plus it's less conspicuous- just in case you forget your device when you leave your car.