If you go there with your Mahal, dont stay at Big Apple, as it is basically a "single place" with many opportunities for entertainment in the bar and around the pool...

Atlantis is great but not really cheap. One of the owners is a british guy
I would recommend Asia-divers, with the highest qualified instructors, and El Galleon. It is a 3 minute walk to Sabang if you want some more "action". A great guy from Manchester (Pete) is one of the instructors and always up for a drink in the evening.
LBC is also a nice place in Big LaLaguna there is also the only beach in the Sabang-Area

If you want real quality and a very good course you wanna think about Asia Divers, Atlantis, LBC... in that order

cheers

Rhoody