Dev Build 3022 is out now.
The primary change in 3022 is the plugin_host<->sublime_text communication, which is now lock-free for the general case. Speed is much faster, such that the API overhead is around the same as in S2. For some actions, such as scanning the buffer character by character, S3 is now faster than S2.
All known crash issues have been resolved as of 3021/3022, with the exception of the Sparkle auto-update issue, which I’ve yet to track down.