My host is fairly solid in my opinion, but if it grows to be huge it'd need to be moved off. However, let's not get ahead of ourselves: at this point a larger wiki provider wouldn't be necessary; the english speaking community is tiny. While a wiki running on a Cray XT5 chilling out with a OC-192 hookup would be nice, it's overkill at the moment.
It's not my call to make, however. :) Just offering a bit of help