Depends on where you fly. Is it Intl. J or NA J ? I ask because of the concierge... For me, that was the best perk of them all! I mostly fly within NA, and having someone call you at 5am to tell you your flight is cancelled because of a snowstorm 300km away, and that you're rebooked an hour earlier is a godsend. Other times I've been stuck in traffic and had them meet me at security with a BP to rush me through, overslept and had them rebook me, or had irregular ops and had them check availability for me over the phone.

There are other benefits as well:

Guaranteed Y reservations-- never hurts to be able to bump someone to avoid sitting in the MLL for 5+ hours.

Irregular Ops-- J pax are priority, SE pax are priority, SE pax in J are the top of the top of priorities in cases of irregular operations. I remember once being diverted and told we'd have 2 hours in Calgary, and the only SE, in J, was pushed onto an earlier flight, while the rest of us stood around and waited as they manually rebooked everyone onto a new A320....

What about vacations? Being SE gives you more AE miles as bonus, priority rewards, and better upgrade priority-- after all that traveling, a relaxing vacation might be nice.

So on a normal day, not much difference, but the second things go wrong, SE sure is nice!