In my experience, the CY brand has been more consistent and just a step above FI. Most of the FIs I have stayed in have had smaller rooms and cheap, flimsy bath towels. The FI in Springdale, AR comes to mind. To me, the FIs have a cheap feel to them. However, there have been exceptions to this. I stayed in a new FI&S just outside of Knoxville, TN that could have easily passed as a SHS had it not been for the lower-tier breakfast. Still, my experience with FI has been more negative than good so I avoid the brand altogether; but that's just my preference.

In the end, it doesn't hurt to do a search either here on FT or over on TripAdvisor to see what recent reviews from your fellow travelers have to say about a specific location.