It technically doesn't meet the Ryanair width dimensional guideline, but I've never seen anyone that close turned away. One warning, I own 4 pieces of B&R (not that particular case) and the dimensions listed on their website have not included the external handle & frame or wheels.
Strictly one item of cabin baggage per passenger (excluding infants) weighing up to 10kg with maximum dimensions of 55cm x 40cm x 20cm is permitted
Dimensions: 8.5" x 15.5" x 19.5" / 21.6 x 39.4 x 49.5 cm
Weight: 8.95 lbs / 4.0 kg
Am sure someone who flys Ryanair more than me can comment on how strict they are.
I'm not interested in this sort of bag because some airlines (I'm looking your way Qantas) only allow 7 kg onboard and I've been checked a few times entering the outbound immigration counter.
Programs: COdbaUA 1K, AA EXP, Kimpton IC, SPG Gold, Marriott Gold, Omni Black, Hertz PC, NEXUS and GE
I wouldn't worry so much about volume as weight. B&R bags, while incredibly well made and supported by a great warranty, are very, very heavy. FR has always weighed carry-on luggage and is even more strict now that they charge big money for checked bags.
Did United get a bulk deal on bad omelettes, turkey sausage pucks and horrible broccoli cheese potatoes 3 years ago or something?