Are all base mounted aftermarket seat frames the same?

[Braveheart]

I'm looking at buying bucket seats for my Clio 172 Cup and there is so much choice out there with the likes of Cobra, Corbeau, Sparco, etc that I thought I would check whether the subframe fitment should be influencing my decision. I will be buying the seats with Clio-fitment subframes.

Are the frames from Cobra/Corbeau/Sparco all the same in terms of quality and seat height, etc?