I suppose everyone has their own way with Flstudio right.
personally i just though that suggestion up cuz i would never aimlessly through compression on something that would not need it. but then again i mostly just use vst's.
basicly what a compressor does is takes all the frequencies of the sample your using and squashes it into the controlable paramater that the human ear can now hear or what ever you set it to but thats what the objective is suppose to be.
the reason I dont like the fl compressor is because im use to be able to see how much you are compressing something with actual meters rather buy " oh ok, that sounds good" because a compressor is ify. the sound may be good on monitors but crap on regular speakers.
By the way this is just my opinion as many other people feel diferently
anyways i just did some searching for like 2 minutes and found this...
http://www.kjaerhusaudio.com/classic-series.php
Ive never tried these vst's and they dont have mmeters but like i said its just an example. just look up "free vst plugins"