I've had a couple of mountain bikes with disks and they worked fine. I've had a lot of bikes (road and mtb) with cantis and V's and they worked fine. All were maintained and adjusted properly.
If I were buying a new tourer I might consider buying one with disks but probably wouldn't because IMO (and it is just an opinion based on personal taste and not an incontrovertible fact so no one can argue with me) they are fugly.