There's parts of The Invasion I really like and I definitely understand why it is loved among many fans.  For me though, it's not even the strongest Cyberman story among the Second Doctor, and I've always been a bit more of a Tomb of the Cybermen man myself.

I'd really like to rate and review The Invasion more fondly, but this is one of those stories that just refuses to stick with me.  I've probably seen that opening sequence where the TARDIS lands near a cow more times than anything in Doctor Who, simply because I have forgotten that I've seen The Invasion more times than I can count by now.  There's parts I like quite a bit - that cow bit, Tobias is a pretty memorable villain, and it's really fun seeing the Brigadier again, Benton's first appearance, and some of the shenanigans in London's sewers.

Yet it all doesn't quite come together into a complete experience for me.  I think that's why I have so much trouble really remembering most of the beats of this story. In between all these memorable ideas is eight episodes worth of pretty inconsistent pacing.  I enjoyed parts of The Invasion, but the whole set of episodes is a little tougher to get through, at least in my experiences with them.  I've watched this a few times now and it just isn't quite for me, but it is fun enough.