While I always liked Rainbo better both because they were “first” in my mind and their main font was more appealing to me as opposed to Colonial’s very standard serif design, at least they both shared the same exact "is good bread" on their packaging with that "g" of absolutely spectacular design. I could stare at that beautifully-styled "g" all day.
The Colonial brand was my introduction to the fact that certain things were reused in different sections of the country; something I had a hard time accepting as a child for many years. When growing up as a young boy during the early 1970’s in Louisville, Kentucky, my mother always purchased Rainbo Bread which had a modern font and the commercial jingle of, "We make Rainbo Bread like we’re making it for our own kids." It was much to my surprise upon moving to Little Rock, Arkansas in 1972 that, not only did I see the name Colonial in the same ovular rainbow logo used by Rainbo, they also used the same jingle.