there's no decision to be made, the merlin wins hands down. Ok so the tds is a little higher but get yourself a reconditiooned di vessel from cleantech and you're laughing. I run a merlin myself, there are also a number of local wcers filling up from my static tanks, all in probably 3500 - 4000ltrs of product being produced each week. The merlin is a year old, prefilter is changed every 19000ltrs (inlet), inlet pressure only 40psi and inlet tds all over the place (was 342ppm 3 weeks ago, last week 92ppm) water comes out at 4ppm regardless. A truly brilliant system for the money.