I think the hate for this mainly comes from it being marketed as the 25th anniversary episode and it maybe not living up to that tag but I actually enjoyed it. There's nothing particularly bad about it, it's just there's too much going on for it to do everything justice in 3 episodes. Some of the action is terrific, especially the scene with Ace and the Cybermen in episode 3 and even if it never came to anything, the hints about The Doctor are intriguing.