Huge variety of the things. Work really, really well if you choose the right one for the job and install it exactly as per specifications. Which, realistically, Home Shop types aren't going to be able to do. If nothing else most of the high performance ones can't be got in small numbers although some of the automotive ones can be found as manufacturers spare parts. At a couple of £ each if the ones I got for my P38 Range Rover are typical.
Plier tool kits tend to come with general purpose, light duty, types intended primarily for panel fixing and holding up fairly lightweight things with multiple fixings. Don't have to be that fanatical about the lightweight side of things, big panels can come out heavy, but I'd be chary about anything over one hand lift weight. The multiple fixing thing is essential tho'. You really don't want the rivnut twisting during installation or when whatever its holding get knocked as any shift seriously reduces its torque resistance and will almost certainly make the fixing irremovable without very serious attention. Important not to over torque the screw or bolt. Some determined nooging around the internet should unearth figures for ones similar to what you have. Way back I was told, possibly by a visiting rep from RS Component (remember them), that something around half maximum torque for that size brass fitting was an appropriate maximum for those they sold. Which, for small screws, isn't much.
You must have a clean hole neatly de-burred on the back. Ideally with a nice sharp corner. In my experience the de-burring and sharp corner bit is where folk get into trouble with blind holes. All seems very variable. Sometimes Mr "I'm in a hurry so its gotta do" can get away with absolute murder and sometimes Miss "usually very careful" gets bitten after what should to have been a quite adequate installation. Really don't want them to turn during installation which is why the bolt and nut trick can drop you right in the kitty litter as can trying to improve the grip by tweaking up the bolt a bit over tight. The grip comes from the collapsing part both mushrooming over the back of the hole and simultaneously expanding to wedge inside the hole. Indeed some types, intended for thicker materials, just wedge themselves in the hole without the mushroom over the back. The wedge in the hole effect is why you need to use the appropriate fastener for the panel thickness. Curious Clive tried a few wrong 'uns and was a bit surprised at how much difference it made.
I think it best to lubricate the fastener with coppaslip or similar. Other folk swear by sealing the threads with the lowest strength loctite. Been known to anoint the hole with supaglue for a bit of extra torque resistance, most likely the feel good factor vastly outweighed any real world gain.
Bottom line is that rivnuts are very forgiving if you don't push the envelope too far too often but that forgiveness means its easy to get in the habit of expecting too much too often. Bit like over torquing bolts. Usually you can go beyond the official limit but eventually you get bitten.
Clive.