Some more subjective compressor trivia...
The curse of compression is noise as the input signal fades. There are subtle differences in the type of noise you have to struggle against if a comp is used first or last in a chain. IMHO comp at the end lets more garbage from the chain through even if this is the modern default approach. Comp on the front end just has to deal with the pickup and whatever fields are being picked up in the background. If you can clean up and sustain the sound up front, the output will be a lot cleaner.
Here's where art, experimentation is needed. One can work out a good compromise in a stable studio environment, but live work in different hum/inductance environments makes it harder to get some magic formula. Playing live, turn at a different angle against the lights or speaker, move a few feet away and everything is a mess.
I've found if only for me, in a stable studio, placing a noise gate after the comp and before anything else downstream works about the best. There are free gates. One link to some of them:
http://bedroomproducersblog.com/2012/01/17/bpb-freeware-studio-best-free-noise-gate-vstau-plugins/ I mostly use Nomad's Liquid Gate if there is not an adequate gate in a suite (Amp 3, Guitar Rig, Headcase, etc)
http://www.nomadfactory.com/products/liquid_II/ The gates in the major commercial suites are good. The gates in Headcase and it seems Revalver can be played almost like an attack filter allowing some really good semblances of hi volume tube amp response. Revalver has sch-1b but it is "The Gatekeeper" that has the swell characteristic. Actually glad I went with the $29 special.
I've got these nice floor stomps but rarely use them even live. My live setup anymore is a bastardized mexican strat going into a Presonus USB 2 box and a laptop. My American strat is mothballed away downstairs somewhere because it don't compare with the mexi monster. Laptop goes into...(don't laugh...)... a right and left stack of two Fender 212r's on either side for 400 watts stereo.
Internal vst comp into a noise gate into whatever else in the rampage.
Choice is out there vst of doing a multi band comp or a single band comp. I found that using a single band comp followed by a parametric eq is far easier to handle and defines what gets fed into the fuzz box.
If the comp is pressed to max compression, there may still be a makeup issue, so IF this is a factor, a good clean preamp may be needed to up the comp signal enough to drive a distortion unit.
Means in the most complex scenario using only vst's...
Compressor or limiter > noise gate > parametric eq > transparent preamp if needed. Then into the overdrive or effect of choice.
Probably common knowledge that if an overdrive clipping unit of any kind is involved, the noise will be harder to tame versus getting the pre processed comp signal fed into a simple flanger or the like.
Got to get the beer out of the freezer before the bottles explode again but have a couple favorite units anyone interested can try. Also some new radical technology or maybe new application of old technology that may be a holy grail of noise reduction if it works as good as advertised.
Best,
John