None of them. Seriously, no one linux distro is really any better than any other when it comes to wireless. The reason is that very few of the chipset manufacturers release info about their chips, so there aren't very many native linux drivers. And that is a problem ALL distros have to live with.
In fact the only distro that really stands out is Fedora, and not for good reasons. The stock Fedora kernels are extremely difficult or impossible to use with ndiswrapper. Since Fedora is a popular distro, and ndiswrapper is probably the most prevalent wireless driver, it's a really bad combination.