The Simaudio 430HA is the best headphone amp I've owned, and I've had many. The Sony TA-ZH1ES is also very nice and includes a really good DAC if that matter. There's a DAC available for the 430HA, but I don't have it so can't comment on it.
Both amps have a lot of power (not that you need that much with the Focals), lots of connection options, hi/lo gain switches, and very black backgrounds.
I have no experience with the other two you mentioned.
Both amps have a lot of power (not that you need that much with the Focals), lots of connection options, hi/lo gain switches, and very black backgrounds.
I have no experience with the other two you mentioned.