Ensemble Darkhorse: Lash is insanely popular among Advance Wars fans. Her trademark evil laugh and the events in Dual Strike might be a contributing factor.
Artix74: Terrible bomb puns aside, she appears to hate the main character as much as I do. This is acceptable, and I will tentatively give her my stamp of approval.
ZeeToo: She's also the only major CO who's openly callous and okay with sending her troops to die. If you subscribe to the "these games are actually nasty wars even if they have bright colors" school of thought, that makes her the most honest, since everyone else is like that in practice.