Originally Posted by i robot
sorry I may not have explain myself clearly. Its the calender aspect of google sync not gmail
I wouldn't do it at this time if I were you. The Google Sync app won't update appointments on the device if another client (BES in your case) is adding events to the calendar. Further, the Google Sync app deletes old items from the calendar in such a way that it sends cancellation notices to all people that had been invited to that meeting that happened 3 weeks ago.
If those 2 things weren't enough, Google Sync will remove appointments from your phone that don't occur during the next 24 weeks. It doesn't delete them from your Google Calendar or from Outlook, but you won't see them on your phone. Using BES, it would place those future appointments right back on the phone. Then you deal with the events not updating on Google Calendar.
For their part Google says that they know of these problems and are working to correct them.