Having watched this anime on and off since it came to this country, I've learned that it's best not to enter a new show with any specific expectations and just evaluate things as they come. My only real hope for XY, especially coming off of Best Wishes, was that it'd be good. And in the first year, I've found XY more enjoyable than its immediate predecessor but nothing has especially stood out to me as anything I'm really interested in investing into.
The main problem I've had with this series is that what's going on, while it's all been handled competently enough, doesn't strike me as all that interesting. Satoshi feels like he's just going through the motions, without anything new to differentiate his journey this time around. No new rivals, no outstanding Pokémon, and no real themes to his quest. The Mega Evolution stuff might have been intriguing, but since none of it has involved the main characters so far, it just comes and goes with the occasional episode or the specials and is thus hard for me to care about. Serena spent most of the year out of focus and has only just started coming into the spotlight, so time will tell just how the writers treat that journey. Citron and Eureka are entertaining, more so than Satoshi or Serena are, but neither feel as if they're being built to anything. Whereas I found BW frustrating, XY hasn't made much of an impression on me at all (which is a shame, because I really loved the first ten or so episodes).
Of course this is only the first year, and we'll be watching this series for two or three more. There will be five more Gyms (including one where Satoshi faces Citron) and a Pokémon League. Satoshi also has to catch at least two more Pokémon, and has also intended to compete in the Battle Chateau. Serena has a goal, complete with two recurring characters in Elle and Sana, and a new Pokémon to bond with. There will be more episodes to focus on Citron and Eureka. There will be new Mega Evolution specials. And the Rocket trio will always be there. There are other recurring characters (Sanpei, Carne, etc.) who will probably be making future appearances. XY has introduced a lot of things it's indicated that it will build on, and I hope the writers will take the rest of the show in an interesting direction.
As far as episodes that've stood out to me, there have been five especially:
XY006 - still XY's best Gym battle, the training scenes were fun, and it brought the main quartet together in a very entertaining way.
Mega Evolution, Act I - I didn't care for the actual episode, but I like the novelty of pursuing another storyline away from the main anime.
XY037 - I love "alternate universe" stories, so I was always going to like this episode. The series' best filler episode so far.
XY040 - this episode was the start of a nice turnaround for Serena. It's too bad that it took so long to get here, but I'm interested to see where the writers take this.
XY044 - not the series' greatest Gym battle, but it's the first one where all of Satoshi's competing Pokémon get to beat an opponent and it's not everyday one of Satoshi's Gym strategies fails from the beginning. Plus, he got to beat a Mega Lucario.