Good DACs rarely (but sometimes, ie tube vs ss) have "huge differences" in sound character IME but have certain "tendencies": resolution, air and open-ness, speed, harmonic texture, accuracy of timbre, PRAT, soundstage, depth, warmth, bass heft. etc. They all are a unique trade off of the above, tending toward some attributes more than others. Select your key sonic priorities and then advice can be helpful. Auditioning for yourself is always better than advice, preferably in your system and room.
A lot of Schiit and Codex owners here. Perhaps they will contribute opinions on your last question. Wadia used to be a huge player in digital, but changes of ownership and design priorities seems to have diminished their presence (but not necessarily their sound quality?) in the past few years.
Dave
