Hi StephenJ77,
If you are looking for a “waterproof” protector that has little effect on the feel of the mattress then the membrane type protectors are really your only choice and either the Luna or the Protect-A-Bed (or any of the rest of the list of similar choices that are mentioned in the mattress protector post or the posts it links to) would make good choices.
If organic or Oeko-Tex certified is important to you then I would choose accordingly but other than that I would choose based on your preference of fabric that is bonded to the membrane, ease of care instructions, and price.
If there are no obvious differences based on other factors … then for me price would be the deciding factor. BobP one of the members here did some good price research in post #1 here.
Outside of these types of criteria I don’t think there are any clear or obvious “winners” between them.
Phoenix