I will say yes. And I'd recommend one of the Panasonics purely for the Panny's Dynamic Range Adjust setting to increase the APL for daytime viewing. But there's also the quieter and quicker operation, and the lack of stuttering that randomly happened on some films (John Wick 2 was the worst offender for me) on the Xbone S.
However, I picked up the Panny UB400 yesterday. All films I tested looked better than they do on the Xbone S ... with perhaps the exception of Unforgiven. It's a weird one. The colours on Unforgiven look muted on the Panny when compered to the Xbone S, specifically the reds. Not sure if it's the Xbone S pushing the reds too much, or something the Panny doesn't like with the disc. The weird thing is, I'm not sure which picture I prefer.