Since 4.4.2 I had two issues:-
1) It would try to connect and then just give up. To fix this I held the Dongle-12345 link down until it says "Connect with pin". This allowed me to connect but lead to problem 2
2) All I got was a blank screen. it seems to make the AllShare Cast Hub go into 1080p/30 !! This is an unusual (but valid) mode that not all TVs support. On my Panasonic TV I get a blank screen but on another TV it works. It seems to totally disregard the TV capability with LF21 or LJ02 firmware and I cannot try anything newer because the firmware updater has been withdrawn by Samsung
Not very impressed!