Quoting Jan Steinman, from the post of Sun, 13 Mar:
I'm successfully using Alias instead of Rewrite. Seems to work fine. I tried Rewrite and did some timings, and went with Alias because it was a bit faster.
my server could be a lot less heavily used so I could not see a major difference in speed like Jan, but it is true that rewrite rules uses a slightly heavier and slower module than the basic alias directives.
one problem with it though, it's only good for wiki under a directory as far as I could tell (/wiki/Page URL instead of plain /Page) unless I missed some important trick.