Unison is also already the name of a file sync program written in OCaml, a team collaboration service, a proprietary newsreader and apparently a security management (access control/intrusion detection/firewall/etc) platform.

The file sync is probably the most popular, and the one that first came to mind.

I realize that the exclusive namespace for software titles is shrinking, but I think that when you already have this much ambiguity, it's not a wise choice to pick generic dictionary word names. Putting some thought into naming things does pay off.