I can't tell you which one to buy, but DJ bikes are built with......
1. Stiff strong frame
2.strong fork with stiff springs to deal with errant landings
3. other strong components to deal with landings/ crashes (handlebars, cranks, wheels. etc)
4. Usually a single chainring up front, usually a chain guide mount
5. little regard to weight savings
6. the ability to drastically lower your seat ( short seat tube)
Don't build a cross country frame and Dj it. I had a CAAD 5 frame that lasted me six months ( i got lucky i guess) from doing the stuff you plan on doing. Don't make the same mistake I did.