Hi Ruben
Experiences - In my first hand experience is SAP BI Quality system (from Windows 2003 /MS Sql 2005 to windows 2008 Enterprise server with MSCS / MS Sql 2008 R2), and we want to migrate all production(SAP BI,EP & XI ) systems to HA environment.
Suggestion - Since you are using the Microsoft platform it’s very easy way to do the system copy method either Backup/restore or Attach/ detach,
Advice - To get the first hand experience better you can try out in your new hardware with different SID and also you follow the links which i already communicated in my privies message
Thanks
Ram