Flagstaff and Rockwood are really the same. I've heard they even are produced in the same building (but don' take that as gospel).
If you look at the lines, they basically match RV for RV. The differences are just usually color schemes inside and out.
FR does this in order to offer competing dealers a different name, but in essence the same trailer. You can have a Rockwood dealer on one side of the street and a Flagstaff on the other.
Once you pick the floor plan you like, then shop it around in both brands and find the dealer with the best price and service.
I was able to find a flagstaff dealer who beat the rockwood dealer by a few thousand.....thus I got the Flagstaff 831 RLBSS instead of the Rockwood 8314BSS