So I received my MKII a dew days ago and There's definetly a huge difference between the new and
original rebel 30.
They definetly went for a more modern sound, without making it sterile. As apposed to the glassy, vintage tone of the MKI, its now just a bit tighter and edgier. The unrefined raw tone of the MKI remains, but now seems to be a bit more "polished" or sculpted.
The clean channel now sounds to be a cross between the original glassy tone and the tweaker 15's plush rounded responsivness.
They definetly kept the "in your face" tone as the second channel really revs up nicely with more of a growl now.
I also think the bright switch on the clean channel is less abrasive than the orginal.
All in all they're both awesome amps, but if I had to choose it'd be the MKII.
I've yet to push the new amp hard and can't wait. I'm sureb it'll sing just like the original.