Regarding the search, I'll be honest and say that we have done very little in customizing the site, mainly keeping it as simple as possible. In the 6 or so years that we've been running, I can't think of more than a few times we had access issues, which were problems with the provider.
I've personally had good luck with search here. Sometimes I forget to use it, but the times I do, can usually find what I'm looking for.
Guess I would have to put it this way... for a site with such a vast amount of information, free to anyone and with no advertising, I'd say there is very little to complain about.