Sonic Frontiers Power 2

I am currently considering an upgrade to my amp (McCormack DNA .5) and would like to hear from anyone with experience of the SF Power 2. I own a BAT VK D5, Sonic Frontiers Line 1 and B&W Nautilus 805 with audioquest interconnects and speaker cables . My listening room is not that big so I dont necessarily need a lot of power but thought the SF combo may work well together particularly with balanced I/C. I see a lot of SF Power 2's for sale 2nd hand at reasonable prices but am not sure if this is a good thing. Does the large number of these amps on the used market indicate a problem. I have gathered from some reviews written that the Power 2 has a slightly fat midbass and may have some transformer hum issues. Any thoughts? (Even McCormack/SF line 1 produce small amount of angry insect noise - am getting a PS power plant to help with this). I am just beginning my search and could just as easily look at Audio Research VT100 or even other solid state. Any help from SF owners or other combinations I should consider with Line 1 would be appreciated.