I have experience with both. I used the 63 nm reds @ 90 wt. I tried them for a couple months but thought they were crap. Dont get me wrong, they work and theyre less costly to use. However, growth is minimal and equivalant to flouro's. In comparison the 600 wt HD cost more to run but the growth is nearly tripled in veg. There is no comparison in bloom. The 600's bud were enormous in comparison in size and weight.