Limiting never used to be really important. When I first started mastering 20 odd years ago, we used to master to 0 PPM. And only when it was peaking over will we use a limiter, a clipper-type one. That left the level about -14 LUFS, which is kind of where we're going back to.
But ever since the TC Finalizer came along, and people started to smash their tracks and work from home with them, the whole mastering landscape has changed. Now limiters are used to get things as loud as we possibly can, whether that's -8, -6 or -4 RMS. But where you want to be is between -10 and -8. If you are using analogue equipment, you usually have to get about 6 dB of gain. A lot of the older limiters can't handle that, so you have to use stuff in the box these days.
The way that I look at limiters is I see them as compressors. What they do is push the sound down to hold the level that you set. What you want to do is use it in the way that you're pushing it. You don't hear them working in mastering; you just want to use them to get a bit of glue. You don't want to smash them, so you hear them pumping, and what I want is a transparent limiter.
Which ones am I using now? My go-to is the FabFilter Pro-L 2. It's got loads of different presets so you can get different sounds out of it. I see it as a compressor because you can get some flavours out of it as you're pushing into it a lot, and it gives that bright flavour for pop music. It can also handle a considerable amount of level, and some will just put +9 on and use only one limiter. I prefer using a selection of limiters, so one thing isn't doing all the heavy lifting. There's also the Elevate plugin, and it's got some excellent style. I also like Slight, but I just use it for the dynamics on there, not for the limiter. They're the three main ones that I'm using at the moment.
That's how I think you should use limiters. Think of them as mastering compressors, rather than as limiters. I listen to them, see how far I can push them, move them around and gain staging through them.