I read over and over that ribbon mics are the shiznit when it comes to recording guitar amps. Don't have one though.
I typically use either sm57, e609 or a condenser depending on what sounds best. There's no one mic that sounds the best for every amp.
Oh, I used to have a couple of CAD e100s and never really liked them on any of the amps I tried them on, but did like them on acoustics and kick drums. In fact, they make great mics for kicks to bring out the "snap" as they take a ton of punishment.