There are big differences between the two positions. 4-3 OLBs are more of coverage, outside containers. 3-4 LBs are like smaller 4-3 DEs that can pressure the QB and cause mismatches. So, what prospects are the best at each position. For the 4-3, my three best are:
Aaron Curry, Wake Forest- His stock has risen and has been a beast this season, leading the Demon Deacons in tackles. A good leader and great player, he will be in the top 10 in the draft.
Clint Sintim, Virginia- This guy is in the top 3 in both categories because this guy is very versatile. He is big enough to play in the 3-4 and athletic to be in the 4-3.
Gerald McRath, Southern Miss- Would be second best in my mind, but he is too small. He will have to play the Will position to have a good pro career, unless he gains weight.
For the 3-4, my three best are:
Brian Orakpo, Texas- Many small DEs will play OLB in the 3-4, and Orakpo is one. He will be a top 10 too, but can go as high as 3 to the Chiefs, who average 0.6 spg, which is horrendous. He is a sacking machine and will be a nightmare to QBs in a couple years.
Aaron Maybin, Penn State- Another DE in college, Maybin is only an third year sophomore. His decision to forego his final two seasons is questionable, but his talent isn't. Making himself a presence on defense, his name will be called inside the top 20.
Clint Sintim- This guy is one of those guys that just explodes during their junior or senior season and his draft stock shoots up. Many scouts have to be looking at this guy because he is so versatile, being able to play in the 4-3 and 3-4.