Yes, Im very pleased with the ATC speakers. Had Tannoy DC10T previously (with several integrated from brands like naim, chapter and accuphase), those were great as well, played different but very well with all amplifiers, more engaging and fun then the ATC perhaps but less accurate and refined, and too big for my room (bass heavy) The ATC fixed the issues I had with the Tannoys, but I might have kept the Tannoys if I had a larger living room.
To answer your question, ATM I have set the audiolab at fixed gain (max +3db). I tested the audiolabs dac capabilities against the master 7 both connected to the master 1 preamp. Audiolab playing a cd, optical from audiolab to the master 7 and acss to master 1, and also xlr from audiolab to master 1. Playing a couple of cds swithching back and forth on the preamp while the cd was spinning I really couldnt hear that much differences even though the master 7 is a multibit dac (pcm 1704) and the audiolab is a delta/ sigma (sabre). The audiolab was perhaps a bit dryer, so Im in favor of the M7. I have an order on a Hiface evo with supply to test the i2s interface on the Master 7 which is the big thing according to many on this forum and others. so looking fw to that.
Anyways, this test also showed me that the audiolab cdq sounded better connected to master 1, than when connected directly to my active speakers, and showed me what a decent amplifier like the Master 1 can give some spark to the ATC. Though the audiolab functions well as a one box solution, is convenient and user friendly the unit as a preamp cant match the master 1 sound wise.