Blue Cat's Dynamics processor is an "all in one" Dynamics effect which can be used as a compressor, gate, expander, limiter, etc. I mainly use it for compression, though don't underestimate its other functions as they can be extremely useful.
I enjoy using this plugin a lot because it can do lots of different things and rewards experimentation. If you want to do basic compression it can handle it no problem, but try turning a few dials, use the RMS/Opto/Peak modes (or different combinations of) and just see how pumping you can make that drum loop!
The visual representation of the curve and input is a massive help, and I'd recommend this to anyone fairly new to dynamics as you learn a lot from adjusting the controls and seeing the effects on screen.
The sound is fantastic, at a great CPU point -- and if you want to, you can oversample the sound when you're ready for rendering (or before if you're lucky enough to have a powerful machine!)
For features it's hard to beat. There's preset loading/saving, built in undo, switchable skins (for example if you're only going to use it as a limiter you have a limiter skin with just two controls). It's got MIDI learn and MIDI control, and used in conjunction with Blue Cat's Peak Meter it's a breeze to have sidechaining, or use an audio stream to control any parameter you want. This plugin begs to be experimented with!
The GUI is fine and functional, and has a neat opacity feature whereby you can make it transparent to see what's happening underneath the plug. All of Blue Cat's plugins are supported by a skinning language, so anyone can reskin the plugin to make it look like however they want. Blue Cat's site offers free skin downloads too, so if you're not keen on the GUI see what others they've got on offer!
The price is not too shabby at all, considering that you're getting more than a compressor, you're getting a full dynamics suite. If you were to buy a limiter, compressor, gate, expander of similar quality it would certainly come to more. Plus Blue Cat are very generous when it comes to previous customer discounts and the like.
The Blue Cat support is excellent. They are available through their forum or email and are active participants in KVR. They've always responded quickly and friendly to any issues I've had -- superb.
I've never had it crash on my, using either Ableton or Reaper with Windows Vista.
In summary, the key word here is flexibility. If you're in the market for a dynamics processor, or something to augment what you've already got, give this demo a spin and see what you come up with -- you might just surprise yourself!