The Rocket is a really great all-round compressor. It's one of my favourites. You can use it in just about any situation and quickly dial in the settings you want. The GR meter is one of the best I've come across and the GUI is nice to look at and perfect in size. It also has an "impetus" knob for adding subtle harmonics which is something I don't think I've come across before. If you didn't know already the compressor is modelled on a hardware compressor known as the UA 1176 which was first produced in the late 1960s.
Stillwell makes a big deal about how fast the attack is but generally I don't use it at extremely short attack speeds. However it's nice to know it does go fast if you want it to.
A couple of critcisms and ideas:
Why are the GR / OUT buttons upside down relative to the scale on the actual meter?
The impetus knob is super subtle until right at the far end of the dial. It would be easier to use if the effect was better distributed across the entire dial.
It would save me a few seconds here and there if there was "dry" and "wet" written next to the parallel knob. Generally you would expect dry to be on the left side.
The difference between the ratio buttons is really very subtle. More often than not I find the differences between two ratios completely inaudible but that may be because I use the parallel and input filter quite liberally. Arguably the ratio button concept was more important on the original 1176. That said however, when used aggressively the "all" ratio setting is rather interesting. It sounds quite sexy on a drum kit. Most of the other compressors I've tried can't do this sound. On the Rocket it's only a few clicks away.
Is the oversample x2 or even higher? I'm curious. This is definitely a great feature.
The HP filter on the signal only goes to 200Hz. I usually find that is barely enough.
The compensation slider runs between -20 and +20 decibels. I have no idea why you would want to reduce the volume by 20, and when used on the extreme settings +20 is not enough. In my opinion it would make more sense to run the slider between 0 and 30db.