Define end game. If you mean when creep waves with giants in them are clubbing the formerly powerful Sedna like a baby seal, then TB's endgame is fantastic. If you're talking about when the opposing team's Beast has Ashkandor... eh, not so much.
I, for one, was not being hit like a baby seal. I'm a little more mindful of creepwaves than that. D:
On the other hand, you were the first one to die to Mageslayer+Akshandor Beast
--
Drasonic:
Early game, the best counter to UB is Erebus (mist).
Mid game, the best counter to UB is Sedna (heal III), Erebus (still mist, this is espiecially true if he doesn't have monk support) and Rook (towers)
End game (giant stage), the best counter to UB is a TB
Artifact stage, the only counter to a UB is another UB and possibly an Oak.
Super-Artifact stage, the only counter to a UB is a UB. Only.