I'm thinking about the hard tri-folding one. Hmm. (Forget the name) But, I like the tracks on the Retrax. I have some racks for my bikes and I use them for that.
I used grey electrical conduit waterproof fittings for the drainlines after the original ones kept falling off. I put the metal ring for the conduit fitting inside the cartridge box, screwed the conduit fitting in. Then I connected appropriate hose to conduit fitting.
My retrax did well for about 6-8 months...then it started leaking along the edges. NOT from water coming UNDER the sides...but water on top running under and into the wheel track then letting it drain into the bed.
It's a good idea, but it doesn't work for me (or my son) the way it should. Having said that, the common denominator is me. I've installed both. (I tried shims, I torqued to spec, I under-torqued, I over-torqued, I twisted as I secured it, I put seals on, etc., etc.)
If the tracks had a higher "curb" where the wheels roll, then it would "gutter" better. It's the gutter failure that has led to all my issues with this product.
It keeps rain from falling directly on my stuff, but the bed gets wet. It gets wet at both ends and along the edges near the middle of the bed.