Happy with my deep6, 2 first stages, 1 second stage. Second breathes very nice. I dive OW shallow, my other regs are SP MK25 EVO S600, 156 that breath well, 109, 108 that breath harder.
Firsts current cost on site, second an earlier cheaper deal. I tore apart and reassembled the second from interest, very simple. Lots of places to mail regs to for service, including deep6. I figure two places local would do them as well.
Edit: The second was a sale last year, $65. The firsts are recent and $245 each, plus some hoses, to create a sidemount setup using the deep6 second and one of my more vintage or S600 Scuba Pros to try out different reg set ups, with an XDeep Stealth and 2x LP50s up and tight with loop bungees. I liked that I can service them with official parts, even becoming official by taking a class. That is rare. I have no connection to deep6 beyond as a customer.