I've had the Tri-Fold for a little over 4 years. I bought it mostly because of the price (much lower than others). It's a decent value, but I've had growing concerns over the quality as it's gotten older. The stitching and fabric that covers the truck bed is very good and I'm pleased with that part. It's also very to install and take off. It takes me at most 10 minutes to install/take off. Most of my concerns are w/ the 4 latches. They seem cheap and fragile. When you latch the trifold on to the bed, I always feel like it's going to break or come off their latch tracks. One latch came off their tracks a while back and it took about 30 minutes trying to get it back on the track using pliers screwdrivers, etc. I've learned to hold the latch steady w/ one hand while latching it w/ the other. The weather stripping on the sides of trifold have also become unglued and fallen off over the years. This is not a huge problem, but it might let some water seep into the bed when it's raining. I'm sure you can glue them back on, I just haven't been worried enough to do that.
On the highway, the cover stays in place. My stuff has always stayed dry too. When you're going 75-80mph, it blows a little in the wind and I'm always wondering when it's gonna fly off but it never does. I only use it when we go on road trips which is a few times a year (and for the few weeks following a trip until I stop being lazy and actually take it off). We took it to Disney World (16-17 hours each way) and it worked great. We've taken road trips throughout the state and it's stayed on. Overall, I'd recommend it if you only need it a few times a year and want a fairly cheap option. I'd have concerns if you want to use it year round and/or use it more than a few times a yea...