The Presonus Comp 16 is a uniquely designed compressor that is easy to use overall. It is an analog unit and has both 1/4 inch and XLR connections, so you can use either an instrument or a mic with it. This isn't a rack mountable piece of gear.
The make up of the Presonus Comp 16 makes it a pretty fool proof compressor to use and is probably designed for those who don't have much experience with compressors and want to get their feet wet with it. The compressor has a variety of presets to choose from as well as knobs for input and output levels and buttons for bypass and output to meter. The unit has three vocal presets, two percussion, three fretted, three keyboard, two stereo, and three for effects. You have to be using one of these presets at all times, making it great for beginners. A manual isn't necessary at all fo the Presonus Comp 16.
The sound quality of the Presonus Comp 16 isn't all that impressive, but it will get the job done for those who don't want too many parameters to play with and want an 'instant' compression sound. You can use it with pretty much any instrument or application as it has presets for just about all applications. The sounds are varied in terms of what you can use this with and all of the sounds can be described as full and wide. If you want a compressor that you don't have to put much thought into to get your sound, this will get the job done for you.
All in all, the Presonus Comp 16 is a nice little compressor for a cheap price. However, I would probably only recommend this for those without any experience with compressors and want a really simple one to get started with. I like to have as many parameters as possible to use and this definitely will restrict that - whether this is a good or bad thing just depends on how you look at it. The Presonus Comp 16 is a perfect place to start if you want a decent sounding compressor that is easy to use, but keep in mind that since it has the presets it will be unlike using any other compressor out there...