In my practice installation simplicity is the most desireful feature.
Quite often you just do not have admin access to server and, for example, database or huge dependancy tree of CPAN modules are often show-stoppers for me.

That's why http://www.usemod.com is the best one Perl-based wiki :)
but even better is the two-file based wikit

What is the dependance tree of Socialtext, BTW?

Vadim.