Differences to iTunes Backup
which iPhone backup is more complete: the backup by iTunes or by True Image? Is some data in one of the backups that is missing in the other? Is the True Image iPhone backup only a data backup or is it possible to restore the iPhone e.g. after a "bad" iOS update?
Elmar, welcome to these user forums.
The iPhone backup by iTunes will be a more comprehensive backup that the one by True Image. The latter is only able to backup data from the phone as does not have any root access to do anything more, and you could not recover from a bad IOS update using True Image.
It's not a flaw of the Acronis product. Rather, it's due to restrictions put in place by Apple. Apple limits what third-party apps have access to, so it's not possible to backup many system settings such as layout.
Someone is welcome to tell me that I'm missing something, but truly I don't see the point of using a third-party tool to backup an Apple mobile device. Apple's own backup includes much more that a third-party app can. I backup my iPhone to iTunes on my PC, and to iCloud. The iPhone backup to iTunes is then of course included in the Acronis True Image backups I make of my PC. Those backups include screen layout and most other system settings, as well as personal data and files such as photos and contacts. I see no value to instead, or even additionally, use a third-party tool that does not include as much as the Apple backups.