We can compare 13 features from the published specs. The JBL Bar 300MK2 is ahead on 3, the Denon DHT-S517 on 2, and 8 are ties. The biggest difference for movies is height: the Denon DHT-S517 has 2 ceiling-firing channels and the JBL Bar 300MK2 has none. Only the Denon DHT-S517 comes with a subwoofer, which matters when comparing the prices.