Phil T, I was in the same boat a few months ago when I was looking at buying my first cyclocross bike. I had never raced cx before and didn't really know much about it. I ended up buying the Disk-R because I wanted disk brakes. I know that's not the most popular thing to do in the cx world but rim brakes seem like a step backwards to me. Since buying the bike I've done two races. One was very wet and muddy the other was dry. I've noticed the disks work better in the wet/mud, but they have so much power and the tires are so skinny that it's really easy to skid. If I had to do it over again I would probably get the Pro and add disks later if I wanted. The things I noticed on the Disk-R are, lower bottom bracket, no top lever brakes, 50 tooth big ring, sloping top tube, road tires. You do get a carbon fork on the disk-r though. Honestly though I would ride both and get the one that felt better.