Just went to mook this morning and tried the Roxanne.
I'd have to say it sound wonderful, clear, and articulate but somehow the 13 put a bigger smile on my face.
Also I think the lowest setting for the bass is 'bassy' enough.
Well, I already ordered the Roxanne so I can't change my order anymore but if I could, I would have ordered the 13 instead.
Though I can't guarantee any accurate information based on the few minutes of listening and my amateur knowledges, perhaps the custom model would sound better.