Instax (I prefer wide for image size) for best long-term viability, worst camera and cheapest per frame. If you go for Polaroid/Impossible, be prepared to cough up $20-25 per pack of 8-10 shots.
As for peel-apart, if Fuji just killed 3000B, I can't imagine that 100C is too far away. Stock up now and prepare for prices to go up if you jump in at this point.
I have an SX70, a Spectra, had a bunch of 600s and Polaroid pack film cams, an Instax 210 but now shoot the Instax in the 210, any Impossible and random expired Polaroid I find in an original silver and brown leather SX70.
Instax and any random Fuji pack film I find get shot in a Speed Graphic as I have good large format lenses that work with the rangefinder and people love that camera. f/4.5 lenses with 800ASA Instax or 600ASA Polaroid stock is pretty flexible without a flash.