I've never seen Negima, sorry ;_;
That's okay, the anime adaptation is terrible. It was made back when everyone was under the impression that Negima was going to be a harem series, and deliberately cut down on the action sequences to avoid driving off harem fans. And when it became clear that Akamatsu did not, in fact, intend for Negima to become a harem series, the series split off from the manga, had a few bland episodes that drew references from older chapters of the manga, then gave itself a sub-par filler ending that made a half-assed attempt to tie up what threads of plot they had actually put into the anime.
On the other hand, the original manga is definitely worth reading. It set itself up like a parody of the harem genre, then spun off and did it's own thing. Negima took and subverted many tropes associated with both harem and shounen genres, and prided itself on the belief "everyone is the main character of their own story." As a result, there are many well developed characters in the cast, and the manga takes the time to explore their stories. Despite the rushed ending, it's a very good series
The second adaptation is better than the original, but also has a plot only vaguely related to the manga. The characters are distinct from their manga counterparts, having had their backstories and personalities changed, and the magic system has been reworked to make it generally less useful. More emphasis is placed on the importance of keeping magic secret, while everyone's competence at doing so (and at pretty much everything else) has been drastically reduced.
The spin-off manga is based off of the second anime adaptation, but retains many features of the original manga. It contains fewer action sequences and comedy sequences than the original manga, and made a much shorter run. I would recommend reading it if you liked the second animated adaptation, but not otherwise.
Avoid UQ Holder at all costs.
There's also a handful of anime adaptations of brief segments of the Negima manga. Unfortunately, you have to have already been following the manga for them to make any sense, since they pick up in the middle of the series and assume one is already familiar with it.