I've been using GooSync, gMobileSync and OGGSYNC for months now and found some oddities with each but overall OGGSYNC seemed the most reliable.
Until now.
I found SyncMyCal has a mobile version (I was using the Outlook version prior to this). Very nice program, nice layout and easy to use. The only thing I wish it had was an auto sync option (which I have requested).
If you're one of many who want to sync your Q with your Google Calendar, this is the one I recommend... I went with the Pro version ($25 one time fee) and couldn't be happier.
Here's their website:
http://www.syncmycal.com/
Some of the issues I've experienced with the others:
gMobileSync
Only downloaded from Google
GooSync
Unreliable sync and caused dupicates
OggSync
Didn't read full details (if location changed it wouldn't update). Also wanted $30/year for pro. Otherwise a good application.
Only on day 2 with SyncMyCal so far so no real issues to report as of yet other than not having an 'exit' option. Syncing seems to be working excellent. (Knock on wood)