The Pendulum Audio ES-8 is a stereo, tube based limiter. It is made up of analog parts and will take up two spaces in a traditional rack casing. I don't know what types of connections it has since the one that I used was already racked up in the studio that I was using it in.
Each of the two identical channels on the Pendulum Audio ES-8 are generally easy to follow and to use. It has parameters in the form of knobs for input, threshold, output, mode for the attack/release, and depending on which way you set the mode, you've got both a knob for preset attack/release and for manual of each. It also has switches for linking and bypassing the channels. If you've used Pendulum Audio gear in the past, this is a fairly standard configuration. I haven't seen a manual for the ES-8, so I can't say how helpful it would be or not.
The Pendulum Audio ES-8 is simply an outstanding sounding limiter through and through. Not only do you have complete control over your sound, but all of the sounds have a very pristine quality to them. It's versatility allows it to be useful for limiting any type of signal from drums to vocals. It also works very well as a mastering stereo limiter if you want to hit your overall levels with it. The ES-8 is definitely one of the cleanest sounding limiters I've had the chance to use.
With great quality just about always comes with a great price in terms of the amount of dollars spent, and the Pendulum Audio ES-8 is no exception. It will certainly cost you a pretty penny to get your hands on one of these, so unless you're a professional with some dough to spend on a new stereo limiter, this will probably be outside of your price range. If you can afford one of these, you know you have a lot to choose from up in this price range, but I'd highly encourage you to at least do some research on the ES-8, as it is definitely up there with the best of them.