For a greenhouse/polytunnel cover, the choice usually comes down to 3 things:
Durability (thickness + proper wiggle wire / lock channel matters as much as the film)
Light handling (clear vs diffused — diffusion can be nicer for even light and less leaf burn)
Condensation control (anti-drip/anti-condensation film is underrated if you’re battling drips + disease pressure)
If you’re in a cold/windy area, double-layer inflation can help a lot with heat retention.
Spec breakdown of film types (clear/diffused/IR/anti-condensation) is here if you want it:
https://greenhouseplastic.com/products