Which kind of storylines/episodes do you prefer? Crazy and hectic storylines/episodes (example: "Lesson Zero")? or more mellow, slice-of-life storylines/episodes? I guess, for the most part, I prefer more mellow storylines/episodes to crazy and hectic ones, because it soothes me more to see a more calm and tranquil Ponyville than a wild and crazy Ponyville for 22 minutes. Not that I don't like crazier episodes (Po1 being one of those episodes I liked). I guess you could also count Luna Eclipsed as a 'crazy' episode that I liked. probably because it had that slight air of tranquility mixed in with it at times. The only crazy episode I didn't like all that much was Lesson Zero. (But, honestly, I don't want to get in to why I don't like it all that much in great detail. Not here, at least.)
personally I like both kinds. Crazy ones are usually more funny, and smooth ones are more hearth worming. although we had 4 crazy episodes in row (ok, Luna Eclipse wasn't that crazy), but I think it's time for some smoother episode now. something like Cutie Mark Crusader Chronicles.
After four fairly action packed episodes, I'm very ready for one about the CMCs, or something less hectic. While I like the crazy episode here and there to spice things up, I see the mellow ones as the show's bread and butter, so those are the one's that I tend to like more.
I must be in the minority, but I loved Zero. I felt that Twilight would have to have a huge breakdown to get the point across or else it just would not be believable. Personally I like a mix, while I adore the warm fuzzy mellow episodes, I do love the classic cartoony ones to since well... its a cartoon and since were never going to have goober dark, long saga time story line. I feel the crazy ones allow for some good old slap stick and Loony Toon type comedy which you just don't see now a days. Which is really refreshing to see again.
I'd say I marginally prefer the more mellow episodes but I've really enjoyed season 2 so far and it's been very much towards the crazier end of the scale... I think one of the great things about FiM is that many of the wilder episodes are the ones that delve the deepest into the characters of the ponies, which makes them a lot more interesting to me than just straight craziness... I suppose I'm saying it's the character driven episodes that I really prefer, and it just goes to show the skill of the writers that they can deal with character development in such different ways.