I go to Camera Workshop quite often. Nelson is quite a good guy, I talk to him most often. Their prices are sometimes the lowest, though not always.
I do agree about John 3:16 though, very friendly guys. Once or twice they quote a marginally higher price than the lowest I got but they never grossly over quote. I think you are quote safe with them.
I think there are two kinds of customers, the shopper and the buyer.
If you are the shopper kind, you are rather undecided. You want to ask around, chit chat, try and deliberate. Then you would want to buy from shops like John 3:16 or Camera Workshop. Many of the other shops are run by Ah Bengs. They treat you like you are from a rival gang. When you look undecided, they get frustrated and grouchy. When you run into problems with your purchases, they treat you like you are one of those bad guys in the Bruce Lee movies who goes around challenging and tearing down martial art schools. They will fight you in order to defend the "honor" of their institution.
If you are the buyer, you've probably done all your home work and very familiar with pricing. This kind of people don't care about service, they pop in, check price, find lowest and buy. If the price is high or service is unreasonable, they just move on. The Ah Beng establishments survive on this kind of customers. Ofcourse, pray hard you don't run into issues with your purchase. Otherwise you will find yourself in the the martial art school challenger scenario once again.
Ofcourse there are the in-betweens
I think those blur young buyers who asks a lot of stupid questions are a boon to shop owners. This is their chance to educate, build good relationships and grow their customer base. If they treat these people well, they will write good reviews in forums like this...