That is a very hard question. Maybe even a year ago I would totally go with anime. I watched it mostly. The music, the colour, the dynamics of each scene that is made is much easier to captivate the viewer, to make you like it, to remember something particular better. It's more clear, what is happening, who's talking and what sound is meant to be produced. Not to mention those marvelous voice actors's ability <3
Of course, in the case of manga, the story is more detailed, many things that couldn't be used in the anime are there and they complete the story very well. Your point of view about the anime can be changed after reading the manga even. Problem is, the twists can be sometimes chaotic and not really surelly stated, so it can make the read quite confusing sometimes. It depands on the drawer and distribution of the panels mostly. In some mangas it's a hard read too and it may take more time than the anime episode would, so it can be time consuming. Although you can of course read it very fast, but again, you might tend to skip parts which are actually quite significant.
And there is another problem of mine. I watch Chinese "animes" They are often addaptated from the novel, which is even more detailed work than manga is (manhua in this case). And in my opinion, these animes are more chaotic than the novels are, often don't make sense, bcs they're very quick paced and yet they still use a lot of long names of not really well known things and in most cases they lack any explanation what those namings are (those are explained well only in the novel). And the manhua is actually an addaptation of the novels too. I don't have a great experience with manhua, it contains some explanations, yes, but tend to cut of the story too much sometimes....and the scrolling till you finally get to the point of the twist....aargh, my mouse is crying all the time. So I would go with the novel wahah, but that is not an option in here...so back to the point.
It is very hard, but if I'd have to choose and didn't count anything Chinese, it's the anime. It was a very close fight tho. I'm so moody that I can't even make the choice according to what would I rather do (watch vs. read). It depands XD But if I'd count Japanese anime only, I would go with the anime option. That's my current final choice.