I love all of Bruce's creations, but the MICA is my favorite. Each of the 4 channels is voiced just right so it can cover many styles of music extremely well. Channel 3 is so alive and dynamic that I could probably play an entire gig with just that and riding the volume knob on the guitar. It always puts a smile on my face when I plug into the MICA and crank it up.
Just happened to be listening to some Chicago and found this clip of them doing "25 or 6 to 4" live on the Tonight Show a few years back. Check out the amp that Keith was using here...you guys will recognize it. Great tone and playing!