In general, the Evangelion mangas are considered good. They expand on the anime's universe, providing more depth and character development. However, it depends on personal preferences as some might find the style or pacing not to their liking.
The Evangelion manga is typically regarded as canon. It expands on and adds details to the overall narrative, while remaining consistent with the core concepts and characters of the franchise.
The number of Evangelion mangas is not easy to pin down precisely. There are the main series and various related side stories and adaptations, so it's a bit complex.