...Looks like it went very smoothly indeed!
I have migrated about a dozen organisations over the past 2 years and the only difference is that the Google Apps Admin & User Mign & Sync tools seem to have got better & better. One migration involved 54 users of an in-house Exchange 2003 server - one user turned out to have >9k Outlook folders - it took >48 hours to migrate - but did not fail;-)