Hi Mike,
There are currently no settings that you can fiddle with to make file changes more responsive - Live Mesh delays the detection of file changes (instead of handling it immediately) in case you do further changes to the file (imagine a text file that you are editing and constantly saving, there is no point in immediately syncing each change - at least not until Live Mesh supports chunked uploads).
That said, if you have encountered times / files that do not sync changes then that's a bug, and you should probably collect your logs from around that time and submit a bug detailing exactly what you were doing (instructions here).
Cheers,
Oren