I stopped watching the first Negima, partly because I couldn't keep the characters straight. So I've made this chart showing pictures, names and voice actresses for all the class-members, and including a brief description of each one. Here's a sample:
The names of the voice actresses are linked to their info pages in the Anime News Network encyclopedia. Images and descriptions are from the character page on the new anime's official site. Some are slightly different from the old anime or the manga, I believe. There are very full character descriptions and images for the old anime on Wikipedia. Japanese Wikipedia is also great. The old anime's official site has a good single page with images and names. The images there link to pictures of the voice actresses, all of whom I believe are the same in both anime.
After two episodes, I'm still not very involved in the story of the new anime, but I think the backgrounds, character design, colors, humor, and overall look are great. Shinbou Akiyuki (the director) just keeps doing his thing and getting better and better at it.