Yup, the AGA Tiamat Plus I linked is basically the same thing, but the top cap is pressure fit onto the atomizer by two o-rings...
With the standard AGA-T you linked, it screws down.
The issue is, if the air hole in the top cap doesn't align properly with the wick, you can get a really harsh throat hit. Almost unbearable... And if it screws down you really have no control over that...
With the pressure fit setup, you can adjust the air hole position to be right next to the wick for a nice smooth vape. Or, if you like you can offset it from the wick slightly which offers a little more throat hit. Point is, YOU control it... Not the chinese manufacturer with zero quality control that just machines the threads and pops an air hole wherever the cap ends up on his drill press
I would go with the AGA-T+ or the AGA-T2. The T2 comes with a pyrex tank, albeit of questionable quality. Some of them come nice and smooth, some come jagged as heck... If you ended up with a jagged one, IBTanked has very nice cut pyrex tanks for the AGA-T style RBA's for a reasonable price ($11 shipped)