(A full-sized photo is available elsewhere).

Most importantly, to my tastebuds, one of the four (the house brand from ShopRite) seemed to have a very slightly different flavor. And the apparent sweetness of the other three was perhaps very slightly different one from another, but that was perhaps influenced by the order that I chose to sample them, as I didn't do a blind taste test. The taste for any of the four wasn't different enough for me to try to choose one as "best" or "worst." In fact, I swept all four powders from the plate in my photograph into my coffee cup for sweetening tomorrow morning's first cup of joe.

All in all, the pricing of the products is the biggest difference, to my way of thinking. Unsurprising, the first company to promote the product (brand name Splenda) is presently maintaining the highest price, and the prices of the new kids vary from one brand to the next. The two cheapest ones each had something that made them distinctive: the clumping for one and the slightly different taste for the other.

If you have been using the yellow stuff, you now have a choice of brands. Try a few of them, and see if you end up making the same decision I did, to use whichever is cheapest.