Maybe it's the scouting reports I am reading but I sure don't get some of the rankings here. Let me share some snippets of a few guys just to see what people think.
12/20/2009 -- I've downgraded Colon's arm-strength and range projections. I still think he has a good chance to stick at short, but there's enough out there questioning his arm-strength that I feel my initial words in the report were a bit to aggressive. His range is downgraded until we see what happens with the leg recovery.
11/25/2009 -- WWBA World Championship, October 25, 2009 (Jupiter, Fla.) (Nick James in attendance) -- Machado showed clean actions and an above-average to plus arm in the field. Range could hamper ability to stick at SS. Solid command of strike zone at the plate.
Based on those scouting reports it sounds like you have a future 2B (Colon) and a future 3B (Machado) and not 2 SS's, it's the range issue. Having said that I don't have a problem with them as draftable players they both seem to have good bats and we could use good players at any position. But like O'Conner they both lack the range (and/or arm) to stick at short and O'Conner has the better arm of the 3 so why in the world would anyone take them ahead of him? Just curious because I don't have all the facts here I suppose but when stacking them all up O'Conner seems to grade out ahead of them, or at least right there with them but his projections got him going much later.
Here is O'Conner's link.