I also use the latest sprite software for device backup. I have never bothered to attempt to restore to another device tho. About the Dashwire, I know what went wrong. There flashes a very quick popup screen that asks if you want to delete or merge the contacts. IMHO, too small to really draw attention to it and too easy just to accept defaults (which you end up getting duplicates)
Fortunately, all my contacts, calendar, to do and mail is on my exchange server and when I setup a new device, and do the first "sync", life is all back to normal for me.
