This is most likely a dumb question, but here goes (apologies!) I'm currently running ST3 3053 and using it to develop my LaTeXTools plugin. I noticed that, unlike on ST2, when I edit and save a Python file in the plugin's directory, it does not get automatically reloaded. The only way to force a reload is to quit and relaunch ST3. There are no error in the console, so that's not the reason files are not getting reloaded. I verified this on Windows 8 and OS X (Lion and Mountain Lion).
Just thought I'd report it; not a huge deal for end users, though a bit of a pain for devs.