Jerry O'Connell or John Stamos
I don't know either personally, although O'Connell strikes me as far more down to earth for a celebrity. More of the type whose able to laugh at himself enough to dress like Clifford at the Ronald McDonald Halloween Charity Party or, who has no issues dressing down to a speedo on the Ellen DeGeneres Show, basically allowing for audience members to thumb his ass like a melon, all for Breast Cancer Research. Less of the type to put his own wife's underwear on Ebay... but that's just me.
In terms of looks, Jerry has this boyish charm that works to his advantage and I think its great that he was able to lose all his "baby fat" from the Stand by Me days. Of course, I also think that he'll be lucky to age nearly as well as Stamos has. Because even if Stamos doesn't look as good as he does in the late 80's he doesn't look his age at all, lol.
Career wise, they're about even... neither has really had a major hit in years and just appear to be "hanging on" and taking what they can, at least from what I can see