I just got a 2nd one last week from fasttech, 1st one is the sjmy, this new one is the SXK version, don't really notice much of a difference in the way they vape, but do like the SXK one more, due to the tank being clear, not frosted like the sjmy.
I think they are great flavor tanks, and as said, very simple tank which is easy to build on and wick. I put a 1.5 ohm clapton coil on mine, and even them are easy to install with the large deck screws.
My only complaint would be the PITA when you go to fill and instead of just unscrewing the plastic tank to fill up, you end up unscrewing the whole tank, then normally for me, I have to find a small screwdriver to stick in the air hole to separate it, but the flavor and how easy to work with, makes up for that con though