I have Both Pre-amps, Plus the UV1. I have owned a number of many other Pre-amps. VAC, VTL, Accuphase, Audio Research, MC, Jardis,Etc etc.
The MP-1 by far is the best I have had, mine is fully optioned with all possibly upgrade. Once you have dialled the pre-amp in with the quiet Tubes (Stay away from NOS) you will never bother looking at another pre-amp regardless of cost or technology used.
The MP-3 Fully optioned is not far behind but obviously no match either.