Like this
1: Season 1, 2 and 3.

In short, i cant decide they are all as good. .__.

Wow... I'd call that a consensus.

Well, I haven't seen them all...but I loved season 3.

Personally, I liked Season 2 the best. I found it to be memorable, though Season 1 has many of it's nostalgic moments. Season 3, after it's finale, just didn't quite do it for me.

Season 1 is where the nostalgy and roots are.
Season 2 was all around refined season 1. It was a perfect followup.
Season 3 didn't quite strike me the same way for some reason. Maybe it's nothing but the fact that I've already seen two great seasons of ponies. (and that we had no proper Rarity episode )

I love them all but eh heh heh i love them in tis order:
Season 3
Season 1
Season 2

But i love all of them!!!!!!!! ESPECIALLY THE ONE WHERE TWILIGHT TURNS INTO AN ALICORN

Season 2 seemed the most developed and catered to fans

I had to say S2, followed by S1 and S3. I love them all, though.

;-; season ... 3 ? *runs and hides*

Season 2, I like the 3 seasons, for season 2 was the best.