My advice is to test whatever backup method you choose to make sure it actually, really, really will work to restore when you need it.
Perhaps it was just my hardware but I had trouble and was unable to successfully restore when I tried to restore from a backup made with the native Windows 7 utility. So I went back to using Acronis, which itself is not flawless either, but it seems to work better for me.
So if you do a test restore and can successfully restore with Windows 7's backup app, then there is no reason why you shouldn't use it, if it otherwise meets your needs.