I went w the sq14 i believe and gave it a go this weekend. for 44 bucks shipped it worked great... and considering my tank has been used for grilling for over 12 months I got a 90 minute boil out of it and still have some left it seemed to be efficient. IT is a bit noisy but brought the 8 gal to a boil in prob 15 minutes. Once it got going I was able to turn it way down to maintain the boil.
Based on looks, efficiency I'd love to have a blichmann.... but didn't have the 170 for the get up at the time.