Buy from all. Then compared and see which one you want to use.

Both are good companies, produces good diamonds. JP's price I think is more expensive than WF/BGD, but if you are in SG, I think you can get the full JP experience by visiting their actual store and probably find the extra money worthwhile. However, if you are not in SG, then buying online is the same from whichever vendor. I will just list down what I think:
JP - Good optical precision, professional sales consultant to guide you, extensive inventory, therefore, somehow it is easier to get what you desire in terms of 4Cs. However, as mentioned, slighly pricey if not mistaken. Got SI from both reputable lab. So if you prefer GIA, they have it.
WF - Value for money price, inventory size is okay, but need more effort to filter out diamonds with better optical precision. Their recent stones that fall under ACA collection series are pretty good though.
BGD - Good optical precision, inventory size is not as great as the others. Slightly more expensive than WF, but should still be cheaper than JP.
Of course JP still win if you somehow need to visit them for whatever reasons because they are just down south.
Hope this helps.
Thanks for the opinion, since its just 1 stone, JP SI the best so far compared to wf & bgd