I flew yesterday with 15.3.4 and did not see wx (several storms within 10 miles) or traffic on Foreflight - though there was not traffic to be seen, at the time.
Weather occasionally worked in the past but not reliably. I found that navigating from the app and back would cause the ADS-B link to be broken. It would not work again until both EFIS and panel were restarted, which I haven't tried in the air.
All that said, I don't rely on either in FF with dual SV1000Ts in the panel. Traffic alerts from FF might, however, be more functional/friendly/detailed than the simple "Traffic" alert in SV. Won't know until that works.