Launching Marketo Plug-in for Google Mail

We're planning to roll out the Marketo Plug-in for Google Mail to our sales development team.

We're only going to sync when a sales email is sent and when a reply is received to the SFDC activity record. So the feed is not cluttered up, we're keeping opened and clicked in the sales insight section.

I noticed that there is a lag time for syncing Sales email received. I did a test at 2:30pm but it logged around 8:00pm. Is anyone else experiencing something similar?

And has anyone recently come across any issues with the plug-in?