Are you getting the A-S amps to replace the AHB2? If so, I'm sure you'll find the new amps a huge improvement. I had the Benchmark in my system for a few months and found it dreaily dull compared with my previous SET amps. I then home demo'd about 10 other ss amps before choosing the NAD M33 above many more costly ones from Accuphase, Mark Levinson, Sugden, Lyngdorf and other less well-known brands. The Class D NAD was a breath of fresh air after the Benchmark, such that I wanted to turn up the volume, rather than turn it down.
We must compare notes as we will some both have new A-S amps! It will be much harder for me to decide which amp I prefer than it will to you, I suspect