I dived with them as a relatively inexperienced diver, so I'm not sure how relevant my experiences are. They seemed efficient and organised. Their day boat takes up to 30 divers, so it was chaotic when everyone was on the dive deck, struggling into their wetsuits. Definitely a 'big operation' feel to the whole experience, but they were set up to deal with the numbers -- everyone had a space in the tank rack and a place to store their gear, and you were expected to return to your spot (might sound normal, but not all the dive ops around here are that organised). All the diving was in small groups -- four to six divers per divemaster. Quite a lot of the staff are German, so there were a lot of German divers (briefings were in both German and English). They also had Japanese and Thai DMs and instructors.
I did one dive with one of their instructors and didn't really take to him (don't think he liked me either, FWIW). Talked to some people who'd just finished their OW with another instructor and they seemed happy. I liked all the divemasters. Have you spoken to the person/people you'll be working with? Do you think you'll get on?
Hope your course goes well,
Zept