I agree the "or" means RW90 is okay. I don't think you are allowed to pull USEI into a complete conduit run.
The point made by brsele is that if you use T90 with the 75 degree rating, you need a larger conductor. It probably wouldn't be easier to pull.
You're correct about not needing a bond in the conduit. If you use 3/0 cu RW90 with a 210 amp rating, the ground to a water line would have to be #3 instead of #6. I think I remember something about a ground plate never needing more than a #6 ground wire.
Interesting about the T90 in a service. We can't run T90 outside in Saskatchewan because the temperature rating isn't low enough.
