Can't really compare it yet as I haven't run through a whole grow with 3590's or comparable even after the first run I just started. Would have to do a side-by-side and quite frankly I don't expect there would be any significant difference, explained below. Compared to some older COBs I've pulled higher gpw with same strains under the 315's.
Efficiency is only one factor though, there's a lot of talk about efficiency like it'll make or break a grow or yields. imo the difference between them in efficiency would be made up in the wider spectrum provided by the 315's if no other supplements like 660nm or 730nm triggers were used with the COBs.