As one of those with an "inappropriate" age gap (me being much older), I think some of the prejudices against us are false and others have some truth.
True:
Financial disparity, which is more obvious as you approach retirement and wish the other person had already "done their bit" too!
Neutral:
Life experience and wisdom: My DH, though much younger, has a wise head on his shoulders
Growing up in a different world: He grew up in a Soviet country, which had much in common with my own childhood (no rampant consumerism)
Musical tastes etc: He keeps me in touch with new stuff that we both enjoy, but obviously we don't get to bop around to old favourites together (except stuff from the last decade, that we shared at the time)
Technology: We're both fairly IT savvy, but again he keeps me posted on the latest developments. It's not like I stare aghast and go "B-b-but what is this newfangled nonsense?!"
False:
I'm not a sex-crazed cougar in denial about getting older
He didn't marry me for an easier life, although he undoubtedly gets one
I suspect the biggest unspoken judgement we get from others is them wondering if he will fancy me in a few years' time, and shuddering to think of the more distant future when (if I live that long) I will be a wrinkly old hag. But to be honest, this is not really important to either of us. He's had so much fun in the past that beautiful girls hold no special fascination for him, and I am glad to be ageing with someone who cares more about my soul than my body.