RAMONYCAJAL  I have been using gSync for some time now, and have experienced nothing but frustration. Synching is erratic, with problems occurring sporadically and unpredictably. Problems include: duplicate entries, entries that disappear from the Google calendar following a sync, and unwanted invitations that appear in all recurring events. I have downloaded a demo of SpanningSync, and so far it has worked without fail. I recognize the shortcoming of SpanningSyc (price, use of their server), however, in addition to the absence of bugs, they have the added advantages that they handle recurring events, they sync alarms correctly, and they perform scheduled syncs in the background; gSync offers none of the above. The gSync website continues to mislead by headlining the claim "duplicates and recurrences solved"; this is not the case. Multiple users have been posting complaints on the developer's Google Group, but fixes are yet to appear (the developers lay the blame at Google's doorstep). In sum, this application is certainly not ready for prime time.  
(Version 1.0.4)