I usually play MST(MM/Servebot/Tron) in casual fuck around matches, even played it at Evo 2k2
Servebot is just not good enough a character to really be much of a factor, his main combos either involve chipping them with the Swarm, or combo into assist(mainly Tron for the damage)
Against Doom/BH, depending on which one is one point:
Megaman on point
Doom/BH - Megaman has to throw those mid range head shots to knock out BH assist, you can crouching fierce Doom when he tries repeated jumping fierce lasers. In close, call Tron to counter BH.
BH/Doom - Head shots to knock out Doom, or Tornado hold, Tron assist will trade or beat Doom. I’d prefer using Tron assist to deal with Doom so MM can chase BH. Instead of Head shots, you might want to throw the 2nd fierce above Doom so you can cancel out BH’s Tower XX HoD and not have Doom absorb the hit.
Servebot on point can just wavedash under Doom’s laser and countercall BH, random Swarms to try and weaken BH for the kill. Alternatively, against BH, the helpers from the sky are you’re best bet to catching BH, MM’s projectile assist is nice in hitting Doom assist in the back, or hitting him clean from the front. Also, short short + call Tron combos into Kobun Giant Hammer
MM’s launcher is alright, not nearly as good as it was in MvC1, it’ll trade with most things, won’t really beat them out. As for Sent’s stomp, no, it doesn’t trade, or beat it, it just… ::sigh:: … just block and push him away…