Are you using yours as a second interface with your UAD?

yes :) I have it as an aggregate device. I only use my UAD as glorified sound card really and I use their plugins so I don't have to use the MacBooks CPU.

I love the ES8 / ES6 combo mainly for piping audio and cv in out of the hybrid set up. Sometimes it takes me a while to set it up but once I have it all working its great to record stuff into Ableton.

In fact I've been looking at all the modulators in Bitwig and have started to re-evaluate whether I could downsize some of my eurorack set up.