Well, it being longer and bigger budget than the show, it Should be better.

Now question is, how much does it expect the viewer to know about the show?
I'll assume that knowing about the 5 alicorns is a must... but is Starlight in it? The friendship map?
I've only missed the last few episodes (been saving them) but if I see it tomorrow, it'll be with someone who's not seen the last few seasons...

You don't need to see the latest episodes to watch the movie. It's completely different.