Let me start by saying this is not our first bed rail rodeo. We have used a few different set ups in different houses for different kids, but though these would be best for my 3 year olds new big girl bed.
They were fairly easy to set up, tedeous, because they come in what I consider to be quite a few pieces, but easy once you get the hang of it. The problem comes when tightening them to use on both sides. They are either too loose or too tight, and it's impossible to find the perfect (and necessary!) middle ground. When they are too loose they are floppy and pointless, they function somewhat better when too tight, but are a pain to work around any bedding more significant than a sheet, and (this is what I see as the largest flaw and why we have ultimately returned them) when they are too tight, they no longer stand upright. They lean in towards the bed instead of straight up at a 90* angle. My daughter was not a fan, and I can see why, it looked like she now had less room and was more restricted than she was in a crib! They did slide in and out easily, but again, that only worked when they were very tight and I was nervous the new bedding we had would get caught or ripped in the locking mechanism. I wouldn't recommend these at all if using on a twin bed, and only use a sheet or light blanket.

Works to keep an elderly patient with mild dementia in her bed at night. This is a double rail since her bed is not up against a wall. The rail isn't hard to install, but you may have to move or remove the mattress, so be aware of this. The mechanism to lower and raise is OK, but sometimes the rails that allow the bed rail to slide between the mattress is a little difficult to maneuver into place. The caregivers will struggle with it a bit, but they've always been able to eventually get it to slide in after a little effort. I think the rails between the box frame and mattress could be adjusted or positioned better which would allow the bed rails to operate more smoothly. This bed rail system has worked now for several months and is worth the price. I'm not sure it would hold up to a child leaning on it or pulling it down. It's mainly used as a reminder and a deterrent to keep the child or elderly person from rolling out of bed.

This is sturdy and does the job. But that's not high praise. The negatives: not easy to assemble or install. More straightforward instructions would help.
The panels are not high enough if you have a very deep mattress. I had to remove a topper and quilted pad to make it work.
And then, if your platform or box spring is not high enough, this will hit the floor before it swings down fully, causing it to sit there at an awkward and inconvenient angle.
In retrospect, I would not have purchased this item.

Cheap, flimsy. The whole idea of it tucking away under the bed is great but in actuality it doesnt work. The tracks slip sideways, the rail is almost impossible to lock back in place. Also there is no way to secure the rails to the box spring (even though in bad English the instructions imply there is a way. Wish I could return for refund but sadly didn't think to keep the box. Also took 30 mins to assemble (and will take just as long to disassemble I think).

A pain to figure out. Honestly. We had SO much trouble trying to get these on the bed, untwisting the straps, and then figuring out how to put them up and down. We've been using these about 8 weeks and the learning curve is now past us. It's very easy for me to put them up and down to make my son's bed. They're blaring white and have ugly screen print warnings all over them, though. Doesn't look great with the decor but c'est la vie. They do the job.