I will easily qualify for E for 2012, but I will land well short of SE. I could probably have reached SE by using miles that went to CO instead even though I had already reached the top tier.

My question is, given that I usually fly upfront, does it make sense for me to actively track my miles in 2012 to get to SE? I checked the AC web site and it seems the most meaningful differences between E and SE are a couple of thousand extra bonus miles and more eUpgrade credits, neither of which is very significant for me. Am I missing something?

no questions asked. huge difference.

Only if you want to use your points for flights.

+1 ^

given that you're flying up front most of the time there's less of a difference, as pointed out being SE has better redemption when cashing in your points, useful if you have a huge point balance and want to redeem flights for family and friends

No real additional benefits to holding SE from what you get flying upfront revenue and being an Elite (assume for US lounge access). Keep your miles going to CO/UA and earn 1K since you won't be hit with all those surcharges when cashing them in as would be the case when using AE miles. You'll also get 100% bonus putting AC flights into CO/UA while being Elite you'd only get half that many. Also, booking one way STAR awards is not always possible with AE, however is easy to do in the CO/UA program (using the CO booking engine) and these only cost half the return "price" while in AE it's about 66% of the return "price". I'm top tier in both programs mainly because I don't fly revenue Exec on AC (just upgraded T+) so find SE benefits of use. Keep doing what you're doing unless you find the merged CO/UA program next year isn't delivering.

Thank you very much. Exactly the information I was looking for!

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!