I would say they are comparable for reliability. All good, solid brands. Clear ray is a UV system. It might help, but you're still going to need to maintain the water, don't let a dealer tell you it's a magical maintenance free spa. I also wouldn't let Clear Ray be the deciding vote in your decision.
Visit the dealers.... some dealers are great and some are downright shady. That may limit your choices right there.
After that, just pick the one the feels good. You're not going to go wrong with any of those brands. If you can't decide, then flip a coin and get the Bullfrog