I've been holding off on trying the IP films for the reasons you mention. I still have a large cache of expired Polaroid films (mostly non-integral, though) and they have held up amazingly well. I have some type 55 that expired in 1981 that still works, although there are some artifacts and odd textures at play. Of course, artifacts are to be expected in 30 year old instant film. I expect more from a newly manufactured product still within its expiry window.
I do respect what IP is trying to do, but I can't yet support them with my dollars until what they sell is more stable and less experimental. Three bucks a shot is a lot for something this dodgy.