I've had good results using external IRs in a DAW but there's a problem. I've found out that when you select "No Cab", the deps E.R., Lo Cut, Res Lvl, Thump, Decay (even the mic!) are still active and change the sound of the IRs in the recording. They should be off in theory but they're not. Nobody knows where the real neutral settings should be so you have to set them to taste...