I've drifted in and out of the use of the reborn SX-70 film. I never read reviews, I just experiment myself. The reason I would drift away was that the material was too inconsistent to be able to learn with and I'd become frustrated with it.
What I'm seeing now is that the PO film, while still amusingly quirky, has become learnably consistent. When I work the exposure correctly ... working within the limited dynamic range and restrictive latitude, etc ... it sings. I find myself not being frustrated, actually enjoying using it. It's not perfect still, but then even the original Polaroid SX-70 film was never perfect when I could shoot with that. (I've had SX-70 film cameras off and on since the late 1970s ...)
While the Instax film is very nice, it doesn't have quite the 'character' of the PO film, and the Instax cameras never have the feel of the SX-70s to me. MiNT's InstaKon RF70 is a very pleasing camera ... their SLR670 series are simply that much better. IMO of course.
It's somewhat important, more so than other film cameras, not to apply modern expectations to these things, for me. I take them for what they are, not what I think they ought to be. And like with everything film, for me, I enjoy it now because of its irregularities and inconsistencies because when I need technical brilliance and accuracy, I just grab one of my digital cameras and I have it.
That's my feeling about it. Might not apply to anyone else, but I know where I'm going when I pick one of my cameras to work with. And it's all good.