Assuming you're talking within the USA, there is a difference in the standard breakfast, especially for those hate powdered eggs.
Comfort Inn standardly has hard-boiled eggs in the mini-fridge. Quality Inn doesn't.
OTOH, Quality Inn usually (but I have found at least one exception) has skim (nonfat) milk for the cereal (I bring my own cereal when staying at Quality). Comfort Inn never does.
I depend on these differences enough that for breakfast variety when traveling by road, I alternate between Comfort for the hard-boiled eggs one morning and Quality for my cereal with their skim milk the next morning.
(I routinely "hotel hop" at Choice because the Choice promos are usually "stay 2 times, earn 8000 points", and you max that out if each of your stays is only 1-night long.)
Of course, all hotel breakfasts have changed significantly since your childhood.
I don't find a consistent difference (that matters to me) other than these breakfast standards. The tend to use similar toiletries, and hotel layout is more dependent on the individual hotel than the brand.