My son has a 7.1 system of KEF Q series. They're Q500 mains, Q200c center, Q800ds surrounds and IQ10 rears (and an SVS PB2000 sub.) He also has a pair of Q300 for his master bedroom 2-channel system. I recently gifted a pair of Q300 for his 2-channel system. I have an R series 5.1 system.
My brother reports that compared to his B&W DM302 Prism speakers, it's no contest. The Q300's hit lower, have better midrange and a smoother tweeter, but the biggest improvement is in off-axis performance. He listens while working in his art studio. Painting large canvas, he's moving around a lot and loves how even they sound across the room, from side to side.
When I compared KEF Q900 against Klipsch RP280, the RP280 did present a room-filling soundstage, but it lacked depth and definition. The Q900 did a better job with placing the various instruments at different depths and locations around the stage. The RP280 definitely went deeper, but to me the subwoofer takes over enough at those frequencies that it's not a factor with a DSP in play.