Sorry to hear that it didn't work out of the box for your repositories. I've filed the non-Unicode text issue here: https://github.com/sourcegraph/issues/issues/32

We're actively working on improving the performance of diff search, but I would expect other types of queries to complete quickly. Would you mind sharing more about the size / characteristics of your repositories? Feel free to email me at beyang@sourcegraph.com if a private channel is better.