I've been there the other season for a day, here's my bottom line:
Flims-Laax caters to the young crowd. Great on-mountain restaurants and bars (which is standard in CH anyway, if you wish). Innovative and patented (hence: unique) trail "rating" system which creates a versatile place, e.g. a "backcountry" (similar to the "Skiroute"-type of skiing) run which is left ungroomed all season. Terrain features built into other runs. Silly: three black diamond rating for a handfull of the higher runs but other than that I really like what they do there, they go beyond the yellow-black-red-blue/black-red-blue-green you find everywhere else.
On the downside: BLP - Bring Long Poles and wax your stix. There are a few long traverses which can require poling, depending on conditions and ski tune.