Erm, just my 2 cents.
I tends to agree with the others.
You wanna to pay $499 to dive and have nose bleed or you wanna pay $509 with everything swee swee?
I'm not saying by paying $10 more everything will be tip top.
What I want to say is the price diff between difference DC in SG is typically between a few $10, maybe $580 to $620.
You wanna find an instructor or DM that is good, not the cheapest one (though it may be).
I need to 3 trips after my OW to know how to dive without experiencing some form of pain.
If the instructor now ask me for $50 more and learn everything during OW, then I will pay for it because the $$$ I spend on the 3 trips is maybe 20 times more.
Just a joke ....
Good and cheap, must wait
Good and fast, must pay more
Cheap and fast, must be lousy
Good, cheap and fast .... don't exist