I need help with an amp decision

Equipment: Tannoy xt 8 (91 dB/Watt sensitivity and 400 Watt peak power ), REl s/510, Black ice f360, and an audiobyte black dragon dac. 
Room size:17x21x10h
Music preference, everything but rap and pop, 
question: Can I get some suggestions regarding a solid-state amp choice for this system, please.
I can not use mono amps because of the sub and I really do not want to go the route of a tube amp. 
Two amps I have been thinking about are the benchmark AHb2 or a first watt ?, I will be trying to shop the used market. Any suggestions, would help. thank you