I bought the individual books in print as they came out and always found myself very eagerly waiting the next one. This is the best manga series I have ever read and one that got me very much into manga and anime. I decided to buy the kindle version, because it is alway a pain to take manga with you anywhere (it fills your suitcase way too quickly!). If you enjoy this series there are also other offshoots including anime, as well as a follow up series by Ken Akamatsu set significantly later than this one (I haven't read it) and a less serious alternative version called "Negima? Neo" (its fun but not as good as this one in my opinion, still worth reading though).
If you enjoy magic fantasy and school comedy romance I would 100% recommend this series without reservation. As the series progresses it gets more and more exciting and interesting, with fan service, humour and awesome battles throughout. The drawing style is great in every respect. Even better the series has a good length and is 100% available in english (I don't think the last omnibus is out yet, but the individual books are still available), so you can enjoy it for even longer and it has a great conclusion. Don't you just hate it when you find a series with a great start, but it ends after just a few books without a proper conclusion, or at least the english language version does?! I cannot find fault with this series. Ten stars out of five :)