In response to someone's question...
Both are incredibly funny.
I think the bar room setting made it easier to come up with new ideas, which is why Cheers endured. Great shows like Cheers, M*A*S*H, and Taxi, could always introduce great ideas because of their unique settings.
.Bar Room .Army Hospital .Taxi Cabs
An unlimited number of new characters could conceivably pass through any of them: bar patrons, soldiers, fares. Because of this, the main characters were always replaceable.
Examples... Diane and Coach in Cheers Henry, Radar, and Trapper in M*A*S*H
While I love Seinfeld, I think that the show is not as resilient as the others because it depends on Jerry. Without him, the title is meaningless. Also, much of the humor depends on all of them being single and how they end up shooting themselves in the foot when dating. I think this will get old sort of like how Family Ties and Cosby did when the kids starting growing up.
For now, I'll enjoy the laughs.