Most used: MU, Chrom (cause you kinda have to) Say'ri, Pegasi, Lucina, Mages, Tharja, sometimes Henry if he turns out better than Tharja in my playthroughs (and that has been like once LOL)
Never used: Every other pre-promote, Donnel, Fred, Sully, Kellam, all knights
I guess everyone else is in between-ey, my teams are always really magic and speed based though ^^