Big Bubble Centre

I took my Open Water and Advanced course with Big Bubble Centre — generally quite good service. The boss Stanley can be a bit scary and tough but he’s a seasoned diver and quite strict on things so safety definitely is guaranteed.
They do dives all around Asia (check wtih them on the schedules), so you can do simple weekenders or longer trips, both based on land or live onboards, though their accomodation always tends towards the more budget type.
The office at Commonwealth also holds their dive shop and gear room. The gear there is generally well maintained and you can try it on at the shop to get the gear you need, but you’re responsible for carrying your gear around once they passed it to you.
Keep a close eye on your paperwork though. I didn’t pick up my open water certification because their old office was quite inconvenient for me and when I did call them up, there wasn’t any trace of it and had to get a new one made.