I loved the first installation in the How to Train Your Dragon series. I thought the voice work was all top-notch, the animation sublime, the story refreshingly original in all the ways you could reasonably hope for (it is a children's movie first and foremost, after all), the best musical score of the year, and one of the most adorable characters ever in Toothless.
The second installation is good, but not as good as the first. The animation is even better and the score is equally as good, if not better, and Toothless is still adorable and all, but some of the voice acting and some of the story is lacking. I'm speaking, of course, about the storyline involving Hiccup's mother. The storyline seems forced and is very tonally inconsistent. I don't think this has anything to do with direction or anything, but it instead has everything to do with Cate Blanchett's overly sappy voice work. The movie is very heartfelt 100% of the time, even when Blanchett's character (Valka) isn't on screen, but her lines sound forced, like she's trying to make them have an impact.
Other than that, though, the voice work is great. Jay Baruchel is again perfectly cast, Gerard Butler gives a better performance than he's ever given in a live-action role, and Kit Harrington is a great addition to the voice cast.
Unfortunately, it's the negatives that have stuck with me more. Originally I was going to award the movie somewhere in the region of an 86 or an 87, but now not so much.