After spending 3 days in Barcelona and then 3 days in Madrid, I am trying to decide whether I should spend an additional night in Madrid and fly home from there, or take the train back to Barcelona, and fly home from there. Does anybody have any thoughts that might help me decide? Are the airports comparable in "niceness" or ease of use? Are the airports equally easy to get to?

Barcelona airport is closer to the city, easier to get to and very nice.
But, adding a day to Madrid ( instead of traveling back to Barcelona) makes more sense.

You don't say where you are flying home to. If there are nonstop flights from Madrid it makes no sense to take the train back to Barcelona. Both airports are close to the city. Madrid's terminal 4 (Iberia/ American) is beautiful. The other terminals so so. Barcelona Prat airport is fine, nothing exceptional.

As curiseluv says, if you're ending you trip in Madrid, why return to Barcelona simply to catch you flight home? You end up wasting a full day of enjoying your holiday. It's far more practical.

Thanks so much for your replies....sounds like staying in Madrid makes more sense, all things considered. (Both flights are direct to Atlanta, so no difference there.) It is always so nice to ask something on this forum and get replies that hlp clarify my thinking.

Stay in Madrid and plan a day trip from there. By the way, stop at my favorite store Artesanias Reyes near Puerta del Sol for gorgeous linens and Spanish souvernirs (not from China!).