How do you make out a high-end amp? Are they affordable high-end amps?

I was recently demoed Monitor Audio GX300 and PL200 (Monitor Audio) on a Marantz 6006 which sounded like the mids were missing. I was considering the Marantz 7005 (which I demoed in another shop on B&W CM08 and CM09) which again felt like too heavy on the bass. Then again the Onkyo TX-NR809 on the same speakers (B&Ws) and they seemed much more balanced.

My question is what is a good high-end amplifier? Given that in Italy and Prague I have limited options, I was considering the Onkyo TX-NR809, TX-NR1009 and the TX-NR3009. Are these high-end (1009 and 3009)?

My idea is that one day to make my cinema surround through the same amp.

Thanks