Feature:
All the controls are laid out in a concise way. At first it seems a little weird to have the "output" knob on the left, because I personally see it as the last stage of the unit's internal signal path. But the knobs are nice and big, the meters are quite readable, and all the stuff you expect - including XLR connections and sidechain - are present.

Quality:
I am weary about taking a tube-based unit with me anywhere. But nevertheless this thing seems to be built like a tank.

Value:
This is the least expensive dual tube preamp I know of. It does not excel at subtle compression (but it is capable). This would be good for somebody who uses several compressors in a recording setup and would like some variety, or a software musician who has access to decent software compressors and would like a little outboard analog warmth and craziness.

Desirability:
What a great retro look. I just love the thing in my rack.

Sound:
I really like the unique sound of this compressor. It is one of the least expensive tube units you can buy, and perhaps as a result of this it is not smooth and transparent. It pumps, it distorts... but it's very controllable. Yes it can be used for subtle compression as well, but there are other compressors more suitable for that.

Support:
I leave this at "10" to not hurt the overall score... I have never needed to contact the manufacturer.

Overall:
I will never part with this unit. It is a welcome part of my arsenal. There are better sounding compressors that cost twice as much. There are also less flexible compressors that cost twice as much. The RP583 fills a compression void somewhere in between cheap solid-state compressors and ultra-rude Joe Meek type stuff.