Full face mask question - Forma vs Vitera

My local supplier has been moving away from stocking the Forma and moving toward the Vitera, and I was wondering if anyone happened to have tried both masks and would have an opinion on them?

I tried the Vitera for a week, but I think after a decade or so of using a mask that has gone under the chin, I'm just used to having that extra support and the Vitera always feels like it's loose or ready to come off for me. I don't know if that's just a matter of me not being used to a FFM that doesn't go under the chin and that the fit is actually the same, or if fitting under the chin actually does provide some extra support/prevents leaks.

If anyone has any insight, it'd be much appreciated.

I have never worn the Forma, but I have used the Quattro, F20, and Simplus. The Vitera is the most comfortable and works best when it is loose on the chin.

Thanks! Does the Vitera get pushed off with shifting overnight? That's probably my other concern with going with a mask that doesn't go over the chin, because I definitely move around a lot in my sleep, but I don't know if that's unfounded.