There have been a lot of negative reviews on this site, which I can agree with to an extent. However, most of them focus entirely on the Endless Eight arc, while disregarding the rest entirely.
I can't say I disagree that the Endless Eight arc sucked; Having to sit through so many episodes of what was, for the most part, the same thing was somewhat annoying. The first time it happened, I had to check to make sure I didn't accidentally rewatch an episode. The changes are subtle enough to miss if you don't watch the episodes back to back.
However, I do like the fact that
the producers tried to do something different, which a lot of others do not. If experimentation like this never occurred, we'd likely never have had the pleasure of watching greats like Cowboy Bebop, or even the original series of Haruhi.
I also very thoroughly enjoyed the other episodes, especially the final ones that very nicely covered the events that had us watch the greatest first episode of an anime ever. And while the Endless Eight arc was long, I really, really loved the final moments of the last episode of that arc.
Art and sound was spectacular, which was always to be expected. You have to hand it to the artists who managed to draw the same episode different ways so many times. The Endless Eight arc was -not- enough to detract from the other episodes of the series, which are all incredible in their own right.
In the end, as long as you're one of those people who only see the negative aspects of something, or have a hard time pushing them out of your mind, you'll probably hate the season.
I personally enjoyed it very much as a whole, and will continue recommending series 1, and start recommending series 2 to anyone who hasn't seen them. And I suggest you not let a few bad reviews deter you from what is ultimately a very enjoyable viewing.