ive heard great things about digitalphsihphones as a whole. quality stuff, even if you had to pay for it (which i don't think you do - at least some of their stuff is free, idk if they have any non-free stuff) (at least thats what i've heard).

I'll throw ReaComp into the mix (literally into it, onto it, under it, over it, whatever).

In terms of features, it has built in adjustable knee size, precomp (~lookahead), RMS size, classic attack/non-classic attack, built in limiter, up to 64x AA and an output mixer (blend wet and dry together plus the regular stuff.
Totally free as well btw.

Personally I like it because it has loadsa features, full automation and has never caused me any problems. As for the sound, well, who knows. It's how you use it rather than the intricacies of it.

SSL has a free compressor on it's site that I use occasionally on drum subs. It can really give drum tracks a raw, "On the Levee" sound.