I like all the CAT amps and Ypsilon amps I have heard. both very special and as a main amp fully worthy of (and present in many) a world class system. but for me they would both be compromises, neither equaling the best of the darts, or best of the ML3's. in my circumstances, the big darts are the main thing, and not losing any of their 'large scale' magic. so PP or moderately powered hybrid is going to fall short as a one amp solution.
as I think about my situation; probably the best way to put it is that the ML3's are honored guests in my darTZeel system. very honored guests.
The Ypsilon Aelius are poor on drive and bottom half and flow on rise and fall of orchestral. Nice tone, but the lack of drive also shows on stage and mids