I'm not sure this service is quite 'ready for prime-time' (although it IS linked to through the main DL.com site, if you look for it).
I have a JFK-LAX trans-con next week, so I thought I'd give it a shot to see what my options were...
1) The site to order meals is NOT DL.com, it's a cobranded airmeals site - and, as such, has no linking back to one's flight reservation/PNR/etc. (you have to re-enter your flight info and first/last name on the site).
2) The list of flight numbers provided on the site is inaccurate. I selected flight #763 with is the 7:00 AM JFK-LAX breakfast flight. It however 'thinks' that 763 is a LAX-JFK 11:00 AM lunch flight. So, clearly, a broken, un-proofed table of fight info. Perhaps no one has actually used this yet...
3) No breakfast options - no red-eye options. alas.
4) The least expensive option is priced at $11.99 (salad). A 'meal' is $17.99...
5) No changes within 48 hours of flight. (no new orders, no cancellations, etc.) So, this rules out SDC possibilities, last minute bookings, etc. And ALL upgrades on these flights are at the gate, no refund, but you still get your meal.
6) Looks like the credit card charge won't go through Delta, but rather thru the 'airmeals' corp... meaning it won't count towards my $200 AMEX PLAT reimbursement for mis charges. :-(
This isn't a very medallion-friendly service IMHO. I rely far too much on SDCs and gate upgrades on my trans-cons and don't see a compelling reason to play meal-roulette with a third party vendor. I like the concept... but the execution is just too limited to be attractive to me.