I didn't even know that swish was still around. I used it quite a bit 5 or 6 years ago to add site search functionality for some websites I was working on. We eventually moved to verity due to the ammount of text we eventually had to search but I really dug swish.
Alive an kicking (ass). The Swish::API XS interface makes it totally accessible from perl with no forking code system calls to get at it. We use the current version to search and index some quite websites and it runs search+custom highlight times in the order of several milliseconds. No stability issues AFAIK.