How about Hafler DH-200/220, Muse 160, ATI, Bryston, Jeff Rowland Design Group.... in ascending order of cost from $200 to $8k
All over an approx. frequency range of 5hz-50khz, and with an Output Impedance of <0.4ohms.
A minimum standard is <0.1% over that frequency range, with similar IMD as well.
So many 'Name Brands' do not even list these crucial specs. I have contacted many and found none to have specs near this range but who fail to mention it.
Where those who do, always list them. Hmmmm. I guess the mfgrs know the difference. The question is, do the users.