Me and my partner did our PADI Open Water courses with DJL and it was great! So much so we ended up doing our advanced too! We had Fish & Damo as our instructors, 4 of us in the group for Open Water and 3 of us led by Fish for our Advanced. Specifically chose here because of the small group sizes and my sister also used these guys and recommended them.
The guys made learning super fun, but also going over everything thoroughly so you felt confident in what you were doing. They were great at answering any questions and going over things again and we all felt very safe and in good hands. DJL also look after their equipment (saw some of the other dive schools not doing this so well).
We also used Koh Tao Pro Video (via DJL) to have our last day of diving filmed and put together into an awesome video. As we had done most of our skills on previous dives (as well as obviously in the pool), it meant the dives being filmed were much more fun and relaxed. DJL are also very sociable, the pool bar always has a mix of travellers and instructors there. Even outside of work hours, they're happy to answer questions on diving and all the guys are a good laugh too.
Davy Jones Locker is slightly more expensive than the other dive centres, but if you want a more personal experience with alot of care and attention, you have to go with these guys! Plus, you also get the bonus of the social side on evenings and when you aren't diving :)