When the migration is complete, launch the Console application, located in /Applications/Utilities. Use the disclosure triangle to show Files-->/Library/Logs/SystemMigration.log. Check that log for any errors by putting the word "error" (without the quotation marks) into the Filter field at the top right corner of the Console window. Many of the reported errors are without apparent consequence, but any report that a file could not be found or copied should be investigated.
The errors I found are:
2011-05-12 11:33:43 -0500 *X* Error : Creating group lp has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group postfix has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group postdrop has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group uucp has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group www has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group mysql has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group sshd has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group qtss has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group mailman has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group appserverusr has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group appserveradm has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group clamav has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group amavisd has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group jabber has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group xgridcontroller has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group xgridagent has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group appowner has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group windowserver has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group tokend has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group securityagent has failed.
2011-05-12 11:33:43 -0500 *X* Error : Creating group unknown has failed.
2011-05-12 12:02:44 -0500 ERROR: Tool returned 1
2011-05-12 12:02:45 -0500 ERROR: Tool returned 1
2011-05-12 12:02:47 -0500 Error creating entry "<use --verbose for full description>" in dsRecTypeStandard:Networks
2011-05-12 12:02:47 -0500 Error creating entry "<use --verbose for full description>" in dsRecTypeStandard:Aliases
2011-05-12 12:02:47 -0500 Error creating entry "<use --verbose for full description>" in dsRecTypeStandard:Aliases
2011-05-12 12:02:47 -0500 Error creating entry "<use --verbose for full description>" in dsRecTypeStandard:Aliases
2011-05-12 12:02:47 -0500 Error creating entry "<use --verbose for full description>" in dsRecTypeStandard:Aliases
2011-05-12 12:02:47 -0500 Error creating entry "<use --verbose for full description>" in dsRecTypeStandard:Aliases
2011-05-12 12:02:47 -0500 Error creating entry "<use --verbose for full description>" in dsRecTypeStandard:Aliases
2011-05-12 12:02:47 -0500 Error creating entry "<use --verbose for full description>" in dsRecTypeStandard:Aliases
2011-05-12 12:02:47 -0500 Error creating entry "<use --verbose for full description>" in dsRecTypeStandard:Aliases
2011-05-12 12:03:13 -0500 ERROR: Tool returned 1
2011-05-12 12:03:14 -0500 ConfMig. Skip /Library/Scripts/Script Editor Scripts/Error Handlers/Message and Cancel.scpt
2011-05-12 12:03:14 -0500 ConfMig. Skip /Library/Scripts/Script Editor Scripts/Error Handlers/Message and OK.scpt
2011-05-12 12:03:14 -0500 ConfMig. Skip /Library/Scripts/Script Editor Scripts/Error Handlers/Message and Return.scpt
2011-05-12 12:03:14 -0500 ConfMig. Skip /Library/Scripts/Script Editor Scripts/Error Handlers/Message if not Cancel.scpt
2011-05-12 12:03:14 -0500 ConfMig. Skip /Library/Scripts/Script Editor Scripts/Error Handlers/No Message.scpt
2011-05-12 12:03:14 -0500 ConfMig. Skip /Library/Scripts/Script Editor Scripts/Error Handlers/Write Error to Log.scpt
2011-05-12 12:03:18 -0500 ERROR: Tool returned 1