Sorry to revive a 4 month old thread, but hopefully this will be helpful to someone, since there are clear practical differences between these two.
Yesterday I auditioned the Dyn XEO 20’s and tried to listen to the KEF LS50Ws as well, but the LS50Ws in the shop were having connectivity issues so it proved impossible. I was only able to audition the XEO 20s (and really liked them, btw), and sadly was unable to make a direct comparison.
The only point I want to make here is these two speakers have vastly different levels of "wirelessness." The KEF LS50W’s require an umbilical cable between the master and slave speaker, while the XEO 20’s do not. Furthermore the LS50W master requires wired connections from all source-types except bluetooth and those connected to your household WiFi network. The XEO 20’s, on the other hand, can be fed all source types wirelessly from Dynaudio’s Connect/Hub device, which does the chore of receiving all the wired inputs (including analogue) and then broadcasting them to the speakers over its own native wireless connection (including to multiple sets of XEO’s in multiple rooms/zones).
In practice therefore, the XEO 20’s are far more "wireless" and can, in fact, be placed anywhere within a powercord’s length of an power outlet, irrespective of the location of your source equipment, and without running a stupid wire between the L & R speakers. This is a significant advantage in terms of equipment placement options, WAF and future-proofing.