My personal review on these 3 seller

ejinutrition
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-Their item are cheap, BUT we need to be very alert on their news (stock availabilities, emails etc)
-Once their stock are finished, they are taking almost like 2 months to restock, so for the customer that usually finished up their supplement fast, you guys better buy more for backup.
-I had a very bad luck experience where their stock restocked on Sunday and I didn't check my mail, when comes to Monday, I just realized about it and then, the stock are completely DONE within 1 day  (this is kind of frustrated as after waiting for so long, I miss it just because of that)
-Overall this should be considered as the cheapest supplement store in Malaysia

musclemaniaclub
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-Their item price range still consider OK, it will be my 2nd option when I couldn't find the supplement I need from the site I want. So far their service are great, the response time of replying customer sms, their processing speed are nice, their packaging very secure and etc.
-If their price can be lower then surely I will put them as 1st priority rather than being alert every day to see from ejinutrition site just to wish for getting cheapest stuff, its not really comfortable for me to deal with it

bodybuildingasian
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-Their price so far can be said to be very cheap (after ejinutrition) because of the FREE shipping. Even the shipping is FREE, their product also stated at a very reasonable price.
-Their response regarding replying customer inquiry is good but the problem is their service is SO SO. I have some experience where my order item switch wrong due to their staff mistake, then I need to deal with the boss friends for refund and at the end I get nothing due to finished stock   
-Then I also obtain a lot of empty promises where the boss apologize for the mistake they did and promise to sent me samples and gift but at the end, there is nothing includes for what they had promise.
-The most sad part is their processing speed are extremely SLOW, I order on Sunday night where they told me they will sent on Monday. Then Wednesday I just got the tracking number and Saturday morning I just get the stuff. It really sucks when your supplement finished already and you wait for such a long time
Overall review, I will put it as my 3rd option and that's it.

Other seller I also go through before but their price are expensive and not yet include any shipping charges. Of course GNC is the most ridiculous place to compare, but among all the private supplement seller in Malaysia, I will say that the above 3 seller that I stated could be the top 3. That's only what I experienced