I think I have to go with Alabama...great punch, Armor 9 and escape death once? Yes, please.
Honorable mentions to Musashi...the destroyer of so many USN battle plans! Just a great brawler! And Helldiver...the bomber that hits like a battleship!
Big E herself, USS Enterprise. Tough, with a good set of rules that make her viable no matter the scenario (makes those Helldivers grgbobe mentioned extra spicy)
The man who gets beat down isn't the loser. The guy who can't tough it out to the end, he's the one who loses.