I agree. this note is performing great. My trusted note 3 has never let me down. Performance is good. I also think note 3 should have got as least 5.1.1 as note 3 has higher specs.
I am not having any problems on 5.0.
But some users do and samsung should give note 3 marshmallow. And its not old in terms of performance. fast on internet etc. lollipop is nicer layout. But maybe samsung could surprise note 3 users. you never know. time will tell my friend.