And that the landlord admits to coming into your house daily to read through all your mail and documents in order to sell you stuff. And then follows you around town to catalog what you buy, what videos you watch, who are your friends, what are they doing, and what information you're looking for, among other things because, you know, this will all make it a better experience for you.
I disagree with the metaphor of the landlord reading your mail: As slightly worrisome as it is, having a person and an algorithm read your mail is not comparable. Of course, the risk is that the results of the analysis is leaked outside the algorithm.
I have taken a conscious decision that I don't care about this risk. I'm putting my money (yes, it's a bet) on Google being able to profit better from advertising to me without violating my privacy. It's a "life's too short" trade-off.
Calendar and contacts, as well as integration with a few other bits, provide a slight measure of lock-in. I'd still have to say that it's lower for Google Apps than for a lot of other products out there.
Actually, the Google Docs integration is probably the biggie.
Re: Contact Lockin: Your contacts should be in the Directory Server and synced to Google Apps. Any first class platform you will migrate to will sync to LDAP.
Re: Calendar I've done two calendar technology migrations for 500+ person companies - they are typically forklift upgrades done over a weekend. You basically lock in your resources (rooms, typically) a week ahead of time, have people rebook any forward meetings into those resources - and have everyone switch into the new system on Monday. As long as people have the right client (in Googles case, that would be a "Web Browser") there is no lock-in.
I could take a 500 person company from Google Calendar, Email, and Contacts over to Microsoft exchange with a team of three people in under a month, with maybe 2 days of disarray (monday) as people (who ignore instructions the previous week) update the mail servers and LDAP servers on their various Androids, iPhones, Macintoshes, etc...
Just make sure you keep your primary directory in your own LDAP server, and you will be good to go. Don't outsource the directory. And stick to something LDAP compatible.
Yeah, it's reasonably light, as I said. Training and end-user usage patterns (never something to be taken lightly) are probably your biggest issues.
Then again, the user experience with the leading alternative solution (MS Exchange) is so miserable that at one organization I'm aware of, the public announcement of a migration to Google Apps for Domains was greeted with a standing ovation.
