Haven’t tried mic pres, but all of my compressors are outboard and, after you set it up, it works great–compensating for delay of each device. I’ve found I need to adjust the input/output of each device in the plugin window in order for them to work at proper levels. My only gripe is that you have to either choose mono or stereo configuration for each device. i.e. If I have two mono compressors (like two Distressors), I have to either use them as stereo or two mono. If I first decide to use it stereo (for drums) and later mono (for bass), I have to reconfigure it in the external effects setup. Of course, you need enough analog ins/outs to have your outboard gear hooked up to your audio card.
You could do the same with mic pres, though you may need some sort of attenuation (a direct box) in your chain.