the bad thing about EX con is that in order to get the most out of it, you'll usually need to use perk 3 greed and use dexterity as well.
Personally, I use perk 1 greed all the time and 5 perks isnt something I run. Saying that on anaked M216 (just prestiged it) Ex con + dexterity did absolutely dominate, but then i unlocked laser + long barrel so its gone, and i dont really want to give up anything else.
All Things Require Sacrifice. http://i.imgur.com/FjisB.gif