Not just Experimental, and the UK
is catching up - leading in Europe, in fact.
For Traffic, if the transition solution of PilotAware and the like doesn't float your boat, there is the uAvionix ADS-B traffic solutions such as SkyEcho.
For real time in-flight weather as in the UK, there has been
a trial running since last Autumn, supported by the CAA and driven by SkyDemon and uAvionix, which transmits weather data from (currently) 3 ground stations in the Southern UK and uses the same UAT kit as is used for the US service. (Sky Echo mentioned above is one piece of equipment that will give you both ADS-B traffic and weather).
