I prefer Backup Assistant. I prefer anything outside the phone for stuff like that, because you never know when problems might occur with the phone, or the SD card or anything.
But that's just me.
But if you change your Gmail addy, that might cause problems with things that are currently tied to that addy. I'm not 100% sure but I think Backup Assistant uses your Gmail addy, just like the Play Store does ... that's why one of the first things it makes you do is sign into your Gmail account when the phone fires up. Be careful with that.