Not nearly enough data to say, which is why I recommend people talk to the support ninjas. A small database with 30 zip files won't sync at the same speed as a large database with 30 zip files when a compaction needs to take place, and two identical databases won't sync at the same speed if one is using WiFi with a good uplink and one is using an overloaded EDGE or even 3G connection. The latency of the WebDAV server also plays a role.
It would be interesting to see the results of running "Speed Test" or similar apps immediately before or after these minute-long syncs being reported.
It would be interesting to see the results of running "Speed Test" or similar apps immediately before or after these minute-long syncs being reported.