I can comment on 2-
TH DI4000 worked pretty well- as a rack mount unit my nit is the input is on the back. Phase reversal is a nice plus... LED's .... might look cool but didn't always correspond to the signal level the board was seeing
The "link" I found to be on the noisy side , however as I wasn't passing the signal through this wasn't an issue. But it's affordable and it doesn't have a wall wart!
HA8000- I wasn't happy with this at all... noisy and the insert caused ground loop problems- Look at the Presonus headphone amps
