Here is my opinion, based on WT results (my recollection, not statistically):
3 week Grand Tours:
1) Nairo: 2nd at TDF 2013, White jersey, Mountains jersey
2) Uran: 2nd at Giro 2013, White jersey Giro 2012, wore (but not won) white jersey in Giro 2011 & TDF), GT lead several times by team
3) Betancur: white jersey Giro 2013
4) Henao: Wore, but not won White jersey Giro 2012, GT lead at Vuelta by team
1-2 week stage races:
1) Nairo: by far, above the others, won Murcia, Basque, San Luis, etc...
2) Uran: podiums, but no wins
3) Betancur: probably going to at least podium Paris-Nice
4) Henao: podium, leader at Basque, but not won
5) Acevedo: Podiums & wins at multi-stage races in US
6) Arredondo: Podium & wins at multi-stage races in Asia
1 day classic type events (with legit Mountains):
1) Betancur: from last year
2) Henao: from last year
3) Uran: from previous years at Lombardia & Canadian races
1 day classic type events (rollers):
1) Uran, way ahead IMO than the others. Worlds, Olympics, etc..
Overall:
1) Nairo
2) Uran
3) Betancur
4) Henao
Too early to call on:
Acevedo, Arredondo, Atapuma, even Duarte & Chavez