Hello,
I am a software engineer at Sharpcast and I work on SugarSync. I am sorry to read that you are seeing this problem. iWork bundles support is something we really want to get to work and we're working on it: you can expect it in an upgrade of SugarSync very soon.
The problem is basically that iWork files are actually folders with a special flag on them - they are bundles. Syncing these properly is a little harder than just syncing this flag though, as the file could get corrupt easily in common conflict scenarios, if we're not careful. But we know how to solve this and it's on the roadmap.
If you happen to see any other file type that doesn't sync well with SugarSync, can you please contact our support team and let them know? This way the engineering team can make sure to build support for it;-)
Thanks for trying out SugarSync,
Jean-Gabriel Morard