Is Negima manga worth reading?
Try reading a few chapters and make up your own mind. It's not like you have anything important to do.
I read it for Nodoka, Yui, Fate and Eva.
Generally speaking, most people say it takes until the Kyoto Arc (Volume 4) to pick up. Not being most people, I'll say the first part is still important to keep in mind.
Also, the manga was pretty much written to shred people that don't read it real carefully. (For instance, the entire thing about how "Love Triangles never end happy?' That was pretty much Nodoka spending over 200 chapters being an idiot.)