All softwarecompressors I heard, produced "grainy" artifacts in extreme settings. Most hardwarecompressors are more sensible for too much - you just cannot push it too hard without loosing the real punch, while softcomps can cope with transients by lookahead and you can push and push and it still seems not to be too much. They distort too, but in the chaos of analog compression is more magic than in the tight algorithms of a finalizer IMHO.
I really love the bombfactory-series on TDM, 1176 and LA2A. You just get not the same SMACK! from software, if you give it that extra push over the cliff. It's more of a ZZACK¡.
And the silky distorsion of the LA2 is slightly harsher in its soft-dependant.
But in the end, some L2 or loudness-maximizer just polishes over the mix anyways, nivelling all those nice little nuances making it LOUD(and harsh see last Chili-Peppers album).
I see more of a problem in the summing before compressing the drumgroup for example. Well, and it's not so comfortable to work with splitted signals - dreaded latency.
Niko