In the vast majority of cases, Simplenote's synchronization works great. We handle millions of synchronization requests each day without any problems. But if you do lose your data, even just a single character, and even if it's not our fault, we want to hear about it. The integrity of your notes is our top priority. Any form of data loss is completely unacceptable.
We're in the process of adding additional safeguards and fallback measures for your notes. Please contact us regarding any form of data loss and try to provide as many details as you can remember about the circumstances that caused the problem so we can ensure it won't happen again in the future.