While many of the non-tube guitar compressor stomp boxes fare just fine, there really is something special about a real tube-driven compressor. Enter the Electro Harmonix Black Finger.
This one really stands out as it warms up your sound very nicely. The control set is quite helpful in sculpting your compression. There are two types of compression “Lamp” and “LED”. The Lamp setting will produce a more subtle compression with a slower attack. The LED setting is much more aggressive. With both pre and post gain, you can use this pedal to really goose your drive in very crafty ways or simply use those controls to fine-tune your compression type. The overall effect is an extremely warm compression that can range from being very transparent to really squashing your sound; all up to you.
This pedal does come with a few caveats though. The downside of allowing for as much as 300 Volts of swing is that you definitely cannot operate this with a 9-volt battery; there is a pretty serious (and proprietary) wall-wart that is chained to the pedal. Also, due to the nature of the two tubes sticking out and a less than military-grade construction, I’d recommend this as a “set it and forget it” pedal that goes on top of your amp.