How does this compare to a traditional flat plate collector?
Of course, the answer must be: the concentrator is way cooler! Seriously, the answer to the question is complex. Leaving aside the economics for a moment, or the perceived difficulty of construction, I did a series of tests this summer comparing the actual measured performance of several different configurations of a DIY (Do It Yourself) flat plate and this parabolic concentrator. You can read about that here: Comparing concentrator to flat plate solar collector. Not surprisingly, both did better when tracking the sun but otherwise they were quite comparable. I think the concentrator had better performance overall and is more versatile. You can decide what is best for you.