I always use Collector 2 in my loadout. It helps me get my Burst Rifle upgrades faster, my armor faster, and my Flamethrower faster. Using Collector puts the points where the kills are, which I actively try to go for more often. I used to use Crafter 3, but felt that the 100 coming from the gifts weren't up to par with the constant parts given by Collector.
In short, I use Collector all the time and tend to avoid other useful survival skills like Crafter and Reviver.