Mic'd amp for me. Actually I've never mic'd my amp cuz I always end up having to just crank it and fill the room with my little 1x12 Peavey and a big boost of the mid knob, lol.
I have been in the situation where I had to run my digitech rp355 amp and effects modeler directly through the system and run my amp as a monitor for an outdoor blockparty concert thing and...
It seemed fine. I'd never done that before, but I liked the sound that was coming out of the system, at least from what I could hear.
But from a purely theoretical point of view, mic'd amp all the way, especially if I don't have my rp355, cuz my solid state amp does have a pretty relatively nice tone when run straight guitar-amp cranked up and with no boxes in between.