When it works, WAFS is a good way to keep data synchronized between multiple servers in multiple locations. It's transport mechanism ensures that only the latest version of the file is being modified.
Room for Improvement:
Two main issues. 1) It can be a bandwidth resource hog over a small WAN link. We would routinely saturate a 3Mbps link with WAFS. This can be mitigated with tuning what gets replicated. 2) In some cases, it can look like the files get replicated because the files have the correct date, file size, etc. However, the file itself was actually all nulls. In our replication case, we had more than 10,000 files get corrupted this way (out of 1.2 million). GlobalScape support basically said that there were issues with W2K8 R2 but the problem actually dated back to 2008 on a W2K3 server.We dropped the product because of the corruption issue.