I slept in Billabong one night and used their diving facilities for two days. The accomodation is simple, room with fan, the bathroom is the traditional mandy, no hot water here

but you don't need it... fresh water is so welcome... Food is simple but good and a nice atmosphere around the dining table between the worlwide divers is warmful.
The diving boat is brand new, spacious, and the guide I had was malaysian. He was just guiding, didn't try to show us any little curious macro creature, nice guy but apparently bored with his job..
I didn't stay at Uncle Chang, but had bad feedback from a friend of mine who dives with us a year ago, regarding diving equipment (old and unsafe) and divemaster not reliable. For the story - Two OWD in the group went narcosis and short of air because he let them dive under 30m and never checked their air
I visited a nice homestay close to Billabong, the Mabul Long House Arung hayat, the rooms are clean and more comfortable that Billabong ones. I would rather advice staying at Arung Hayat longhouse and use the diving facilities of Billabong (it's a daily rates).