I read about a guy online who did the comparisson test between the 2 QBs, with red & without. Apparently there was no noticeable difference between the 2 plants grown in the same conditions. Don't have the link, sorry.
I've been shopping around for QBs and the best I can find so far is R16k for a 600W LED QB with LM301h 3500k diodes + 660nm red from epistar. Still feels overpriced but is that the going rate these days, more or less?