I have spent quite a bit of time using different amps with the Legacy Focus HD speakers. I have used, Dussun V8i, Monarchy SM-70 Pro, Eastern Electric M-520, Jeff Rowland 501 monos, as well as Melody, McIntosh, and Pathos amplification.
One of my favorites is the twin Pathos Classic One MkIII integrateds in mono config. The Jeff Rowland monos with proper preamp are less warm but have impressive power and sound stage. If you are not out to drive the speakers to broadcast/"live" levels, then the Monarchy are wonderful, rich sounding economical amps. You will, however, get much better transients with a more powerful amp.
The best sound I have ever achieved for the Focus HD is with an amp(s) I am currently reviewing, so I will not disclose them yet. The review will not be out for several months, as they are just arrived. They are by far the most powerful, clean sounding I have used. Legacy speakers are thrilling when driven by big power.