I don't like that much the superleads. To my hears the 2203 is a much better sounding amp, and I think the 2203 (JMP MkII and first JCM800) is the absolutly best marshall amp ever.
however the 60's 4x12 cab that used to go with the superlead is really an excellent cab, it sounds incredible with a 2203 on it. 8)
Good rock'n'roll never get old.