For me, MangaDex is great. It offers a good user interface and frequent updates. However, it's important to note that the availability of manga can vary depending on licensing and legal issues.
Webtoons is also quite good. It has a variety of genres and often updates with new content. However, the selection might be a bit limited compared to some other sites.
It depends on your preferences. If you like visuals and sound, the anime can be great. But if you enjoy imagining things on your own and taking your time, the manga might be for you.
I don't think so. Reading the manga can enhance your understanding and appreciation of the anime. You might notice things you missed before or gain a deeper connection with the story and characters.