Migrating domains already on Google Aps

Is there anything to consider when migrating a domain from one provider to another, when google applications (gmail, etc.) is involved? Certainly I have to add the MX settings on the new host, but specifically, I have a few email accounts, and several hundred emails, that google absorbed. Is there any chance, however small, of data loss - or any additional steps of cautions I should take.

Probably a stupid question, but I just want to ensure I've covered all the angles.

Thanks