I have a Trio. It was my first purchase and like the OP, searched around for compatible stuff before I bought my 510 kit. That was when I found they worked together great. I use the atomizers all the time with my 510 batteries and lots of "puff-puff vape." So....??? I also use it the other way around..my 510 atomizers with the trio batteries. The only incompatibility are the cartridges because the thickness the diameter of the atomizers are different and the way the carts and atomizers work on them is different, so the atty-cart system isn't interchangeable. But lots of puff-puff vapes going on here. Actually, I like the trio atomizers as they are the only ones that have lasted for me and still work like a champ. I should hope so at $20 a pop. I don't like the cartridges, though as the cup that holds the juice is way down inside the cart and it's teeny-tiny, holding only about 3-5 drops. I mainly use them today for testing new flavors.
Johnson Creek sells empty cartridges that fit the atomizers that come with the trio, which is a considerable savings, as well.
Edited for clarification.