NB: I tried both slowphil's custom build on github and the native windows binary downloadable from the main web site. Typing lag (estimated at 500-800ms) is totally unacceptable in both instances.
I can understand, but please appreciate that the task the program has to perform to process typing is quite complex, especially because some delay is needed to allow keycombinations. Anyway we plan to improve responsiveness in the future. Thanks for the feedback.