This is what my field IT network engineer emailed our folks in Central America in regards to the use of Outlook as an email when using Google apps.

We realized there is no longer a good reason to keep on using it, I know his email sounds like a commercial but it is genuine.

As you know Outlook implies PST files, that need to be backed up, copied once we reformat a computer, if it grows too big becomes a problem, if they are popping and the connection is slow or get interrupted they run the risk of Outlook restarting the download process again so they get duplicate emails and well i can continue naming issues. We are going to enforce the use of the Gmail interface since there is no excuse now that the offline feature is available. Here is the email he sent. 

Hello,

Speaking of Outlook...the best option available would be to not use it and use instead the Google Apps web interface (start.yourdomain.com).  Google Apps provides so many options and features and is constantly getting even better-you already have shared and private contact lists, shared and private calendars, high-speed secure email, shared docs and spreadsheets, intra-office chat and video, excellent search and organize capabilities, etc. and most of this is now available on mobile devices as well, and it is all synchronized.  Google Apps gives you full and secure access to all of your emails, appointments, contacts, docs, spreadsheets, etc. from any Internet-connected computer in the world, most handheld devices as well--and you aren't tied to the computer that Outlook is installed on.  Gmail has an Offline feature now that allows you to open Google Apps, read and compose emails, check your calendar, etc. on your computer with no Internet connection, and the way that Gmail allows you to organize and search emails is also superior.