Personally, the anime for Attack on Titan was better than the manga. I don't know if season 2 will decline in quality(probably not. they're taking their time), but the first season was simply amazing. And considering how intense the fights are, it's more interesting to see them in color and moving(instead of in a few pictures).

Don't get me wrong, the manga was still great. Though, the quality of the anime is unbelievable. No episode is rushed, and the pace stays the same throughout.

Hunter x Hunter (2011)

Its the best

Typically I prefer manga, but I much prefer the anime adaptation of AoT. The art style of the source material isn't really to my taste, the Titans looks creepy...but so do everything else. Usually I don't like censorship either...but I personally prefer the changes in this case. I don't need to see my favorite characters' entrails...seriously.

I prefer the Hunter x Hunter anime over the manga due to the art style as well. Can't think of any other examples off the top of my head, usually manga do a much better job at pulling me in.

I'm more of a Manga person.. can read at your own pace and skim through parts that are less interesting

With exceptions, of course

I own inuyasha and full moon manga only, since they're my favorite anime,funny thing is I have not read it yet (I KNOW RIGHT)

I just can't choose a book with pictures over animation,emotions and sound but that's just my opinion.

Parasyte did an incredible job. Check it out.

Also quite obviously, FLCL. I dunno if anyone's read it, but it's utter insanity. Makes no sense at all.

So I can only talk about one piece because that the only one I have read and watch. Back in the day I enjoyed the anime more than the manga but nowadays the anime is close to being trash, mainly because of the atrocious pacing.

Attack on Titan is one

Hunter x Hunter 1999 for me too, drawings are much better than in the manga and some episodes were pure art (Drawing, animation and music wise). It's a shame we had to wait so many years for another anime to continue the story (I like the 2011 version btw, the ant arc part at least)

The WataMote (It's Not My Fault I'm Not Popular) anime had a vibe that was more sympathetic to the main character.  In the manga, it felt more like she deserved her fate, which was kind of grim.

I'd rank the manga for Defragments slightly ahead.  Being a bit more concise actually made it more funny, plus Takao's boobs were more impactful.

You can't replicate that with static images.

Yuru Yuri is much better in animated form.  The voice work, especially for Kyoko and Yui, really makes the characters come alive.

I liked the Skip Beat anime better because, at first, the Skip Beat manga is kind of cluttered and unpolished.  The mangaka's work gets a lot better but I remember thinking that it was hard to follow.

Same with Shirayuki-hime.  I dropped it after the first chapter because it seemed amateurish.  The anime felt like a superior and more professional product.

Chihayafuru is a great example of an anime that's amazing, not because it's better than the manga, but because it does a great job bringing to life the action parts of the manga.  I honestly love them both equally because they do different things well.

An excellent anime will always be better than an excellent manga. A manga can only have good art while an anime can have good animation, good music, good voice acting, good art style and good sound effects which make for an overall better experience.