Some early episodes seem amusing, although I have problems with the, ahem, reactions that seem to go hand-in-hand with the activation of provisional contracts. Nope, there's definitely nothing suggestive going on there, oh no.
Negima also definitely has issues with having way too many characters, I agree with that. That said, I also agree that the art style and direction seem considerably improved compared to the Xebec version. I've seen enough episodes of both, for example, to see that the early Evangeline story is better in this version.
Alas, dedicated manga fans seem to be constantly frustrated by the odd tendency of the anime to not stick to it, so I seem to be better off for not being one of them. Last I heard though they were starting to adapt certain manga arcs in special OVA's, sort of like what's happening with Tsubasa, so maybe there will be some rays of hope for you serious fans yet.
Ultimately, this is something that I find "acceptable" but I'm probably not willing to make it a permanment part of my collection considering the alternatives I have to choose from. If you really really like anime comedy though, this is not a bad pick. I'd take it over others that try to get a laugh by being as over-the-top wacky as possible.