Well, i would say that the ls35/a is easier to drive compared to m5, even tried on es11.  the first try i was using a unison research simply 2, when i tried the comparing.

Then i changed to another amp, sonic frontier power 1. where i compared again, then i realised that the hi freq is more pleasing to listen to, comparing to low power simply 2.

Well all this is based on what i feel and how i think. as u can see i mainly play with tube amps, i am not sure how it would peform on a solid state.