Sandman. Triple Immunity, able to decrease opponents power gain and regen via Petrify while being able to counter evade and unstoppable. Has a high physical resistance with pretty solid heavy attack damage. Most of all, he is ascendable right now, so that's a better feature as well.
thank you @THUNDERBIL Very informative
I would say Havok is better in BG, Onslaught counter and a trap defender.
He is a great Onslaught counter, but so are many others, but he is not that great of a defender. So many champions have access to armor ups now, he can be easily countered.
So is Sandman, really easy defender. But he will be useful for questing and other stuff as well. Also Sandman is a better attacker than Havok and not situation based like him.
Yeah, overall I agree, Havok is very situational, which is why I said he is a trap defender. Sandman might not be bad, but honestly I haven't seen Sandman much in BG actually, even some people who ranked him up doesn't pick him during the actual selection. Which is why I suspect he is not good in BG, I personally haven't used him much.
I don't use sandman on defense, he is really easy to deal with and you can come out with almost full health points.
But I do use him on attack. His decelerate is a great counter for pesky situations and his heavy root combo really kicks in. Not the fastest, but the safest bet.