These days the only mobile gaming I engage in is on my iPhone when on the bus, train, etc.
Several years ago I packed my DS Lite in my suitcase when holidaying abroad but never really used it outside of the hotel room.
To be seen playing a GameBoy, Lynx, GameGear, PSP, DS, etc., when out in public? Not for me, thanks. That'd look way too nerdy, lol! Gaming in public on a smartphone seems to be more socially acceptable. Gaming in public on a DS, for example, when one is an adult male well past his teens looks rather tragic, imo!