Please assist me.
I have used Office 365 for 2 years, great tool but I have my misgivings on its performance ..
Eeeek That's tomorrow @tichdxb,
The only advise you need now is to backup everything, I mean the lot. Addresses, emails, everything you would need. Be thorough!
I don't expect there to be a 'transition period', just in case. There might be? You need to speak with support about this asp.
You know what you are going to be busy doing today if you have lots of email data. Office 365 may have 'misgivings about performance', but not so your clients with you if you loose their data!
Backups are your responsibility.