New Amp Choice (A or B)

So I'm considering a new amp to go between my Benchmark HPA4 preamp and Montana XP speakers. My 2 choices are The Benchmark AHB2 amp, or the PS Audio M700 mono amps. My speakers are 92 db/W at 4 Ohms, but I was wondering if the Benchmark was enough power, or if the M700' were a better fit with my 7 driver speakers. Normal listening... never killer loud. My current amp is just an old Adcom filling in.