Definitely Non uniform
Don't get the stares and dumb questions 'aren't you supposed to be in the cockpit Capt.?'
Able to have a drink or two without braking your company's drink/uniform SOPs
In any case if you are in uniform as pax you are still, from the security point of view, a passenger
I sort of figured that, but I had hopped that with having to travel a lot (especially international) the procedures overseas were a bit more "crew friendly" and that the on-board staff would bump you up to business class/first as a gesture of sympathy.. so much for my naive take on how things work..