Haha ... where have you been Drasca ... peeps were even asking about you yesterday. If you are missed, then you must be loved really. 
Zan the Man has a Plan
The Mojave wasteland, and Fallout New Vegas slaying Caesar's Legion,
I would also say that my advice would be when selecting a character to use for grinding, to select the one that generates the most xp, not particularly kills things the best. I tend to generate the most xp through support using Luka over xp from damage with Izzy or Hall. While I feel that Hall does more damage, the way xp is awarded is not always 1 to 1 with effectiveness.
This is good advice. The caveat to that is the team needs to be able to pull through with your chosen kit.
My primary advice is to use the one that
A) Is fun
Works
C) Works best within the team you're playing with
Instead of blindly focusing on just one class/kit disregarding what other players use, play with team synergy in mind. Like, if you see another reaver, play an ele or reaver to complement them.
By playing more efficient team synergy kits specific to the group you're playing with, you'll gain more promotes per time.