Here's my take on discs:

if you ride in wet/mud a lot you need them, or ride DH. Other wise they are nice but not necessary, just an great upgrade. I ride in dry conditions 80-90% of the time, so I have a hard time justifying the $300-400 it would take to upgrade. Not that I wouldnt' love to have them...I wouldn't base a purchase of a particular bike on disc brakes or not.

If you are concerned about weight, they add weight. You have to be carefull about which type ( hydralic or mechanical) that you would get as some are service nightmares.

In my region, less than 20% of the riders I encounter have them, but if you go over to the wet side of the state, where they have 8 times the amount of rain we do here, lots of folks have them.

Irulan

Just for grins I checked the current online Kona catalog, and I was surprised to see how many bikes did have them. Avid Mechnicals are supposed to be the best from what I have gathered.