Anthem STR vs Benchmark AHB2

I'm leaning toward purchasing a pair of KEF R11 speakers (8 Ohm, 90 dB sensitivity). I'm considering the following and looking for feedback -- I realize that having the ability to A/B the following is likely rare, but open to all feedback. Additionally FYI, I'm leaning toward pairing an Anthem STR preamplifier for 2.1-channel processing. Will then be leveraging the Home Theater passthrough of the preamp for 5.1 surround -- surround processor yet to be determined (preferred eARC compatible -- open to suggestions).

a) Option A: Anthem STR Amplifier (400 Watts/channel into 8 Ohm, 121 dB Sensitivity) vs two (2) Benchmark AHB2 amplifiers configured as separates in mono (380 Watts/channel into 8 Ohms, bridged mono, 135 dB Sensitivity)

b) Option B: Go with either Anthem STR Integrated Amp+Premap (200 Watts in 8 Ohm, 114 dB Sensitivity), or, a single Benchmark AHB2 amplifier (100 Watts into 8 Ohms, 132 dB Senstivity, +Anthem Preamp).

Mostly interested in the perceived sonic differences (if any) between the various options with the paired speakers. Additionally open to other suggestions.

Thank you!