So, the long awaited release of another Haruhi Suzumiya anime is, in fact, the repeated airing of season 1 (that was aired in 2006) wth 12 episodes added. How does this play to Haruhi fans?
The story revolves around this school girl called, Haruhi Suzumiya, literally. She has god-like powers yet doesn't realise it. She forms a club that aims to find Time Travellers, Espers and Aliens - guess who 3 of the members are? The only normal person in the club is Kyon, who is Haruhi's secret love interest yet he prefers Mikuru Asahina. The anime follows how Haruhi "uses" her powers to change the world and how the other club members react to it.
Having watched the first season back in 2006, then having watched this, there wasn't really big twists or that "WTF?!" moment like there were in the first season. I don't regard "Endless Eight" as a twist or WTF?! It's purely another category of it's own and was completely un-called for.
As a KyoAni anime, animation quality and background music is great. The usual cast has returned for this updated season 1 re-airing as well and do a great job.
I didn't enjoy the opening theme, at first, but having heard it so many times now - I enjoy it. My only concern is why do most of Hirano Aya songs involve her shouting? Personally, I like the new opening sequence to the first season. The ending theme is good at best.
If you're a Haruhi/KyoAni fan, you should watch the new episodes (excl. all of Endless Eight, watch ONE episode then move on) but it mainly fills in what the original episodes leave out.
p.s. People regarding this re-airing as a "Second Season" are misinforming people. This is not really a second season, more a "Season 1 PLUS" or whatever additional-like subtitle you want to use.