This guy is the perfect counter to the cleanse team meta and I'm surprised I don't see more of him at the top. I think it's mostly because there's just no room for him on top sides. I know mine had been sitting on the bench since running zeta Maul Sith team. But I decided to resurrect him and see his usefulness. And man does this droid make a huge difference.
zMaul, zSavage, Nihilus, zKylo, B2 is what I've been running the past few days. (Plan on using SA once she's geared a bit more)
There's a few different variants of the cleanse teams but for the most part they have no way to stop B2. And with Chaze/GK's retribution always countering, B2 can dispel/buff block faster then they can cleanse allowing you to target who you need to. Now he does have some weaknesses. The big one being Sith. Daze, shock, stun all effect B2 quite a bit and could render him almost useless. I think the big question is, who do you replace? For me Chaze was sacrificed but it's paid off imo. On defense I think I'm more of a target since missing a taunt but offensively it works extremely well. As for mods I've tried giving B2 more speed, in case he gets dazed. Moving away from the +accuracy he did have.