That was part of the reason i decided to have it modded, mike's impending retirement, although i can't confirm that he already has. IIRC, i think monstatone can do the mod for you.
The other reason was to give it more responsiveness/sensitivity to the lead channel.
Prior to the mod, my mark iii had a very aggressive, pushed tone which reminded me OF WHEN PEOPLE TYPE IN ALL CAPS!
It had a certain appeal, but i didn't want to be shouting all the time, and the mod gave it more of a singing tone.
Here is a thread in which i posted pics of the head when i first got it:
http://forum.grailtone.com/viewtopic.php?f=3&t=26907
Here is a thread in which another user posted before & after clips of his mark iii+:
http://forum.grailtone.com/viewtopic.php?f=3&t=18411
And here is a thread in which i commented on my modded head:
http://forum.grailtone.com/viewtopic.php?f=3&t=27879&start=15
I haven't played any other mark iii stripes, but i think that the mark iii is a very well made amp with great tone. It definitely deserves the respect and reputation it has gained throughout the years.