Klaus at Playa Scuba is also very good
That's who we use.
We know where the shop is and can get ourselves there from the ferry, but the first time we went they had someone meet us at the ferry to guide us to the shop (not far) where we did some paperwork, discussed plans, and loaded up the truck.
You'll probably want to hire a triciclero for your gear unless you're a big fan of lugging it.
Dos Ojos is fun. Don't go off the line.
Stopping at Tacos el Arbolito on the way there is a big part of the fun, as is stopping at Taco Paco on the way back.