Since there are almost no others I'd thought I'd post my own Aeromexico Business/Clase Premier experience in December 2014

I flew a domestic flight from TGZ (Tuxtla Gutierrez International Airport) to MEX (Mexico City). When I was booking the cost for the upgrade directly via the AM website was around £40/50% vs an economy ticket (£120 vs £80 per pax). I thought it was probably worth a try since I don't fly with Skyteam and therefore have no status and I presumed an international airport would have some form of lounge to use. The flight was on an Embraer E-190 with a seat map per seatguru, and as a couple we sat in 2C/2D.

My experiences:
Check-in: There was a dedicated priority check-in desk, which was fine but insisted on us using one of the Aeromexico baggage tags to write our name/details, rather than the numerous other tags on the bag... a bit odd.
Lounge: There was no lounge (I did find a short list here, wish we hadn't got there so early (the airport is pretty far out of town). At least the airport had free wifi, a Subway and a bar so you could create your own (paid) lounge experience...
Boarding: Priority boarding was well done, with business class being called first in a separate queue that was policed with a polite check of boarding passes
Seat: Was large and comfortable in a [1-2] configuration, per this picture, though with more in the cabin. For our two seats there was one blanket and one pillow which was a bit of a miss in service. However in comparison to economy (2-2) it likely wasn't that much more comfortable or private. No video/audio or power sockets
Food: A bag of spicy nuts (that were tasty if very salty), that was all for a ~80 minute flight, tasted better than BA domestic in the UK - but with less quantity
Drink: A single drink was brought at the start of the flight, it looked like there was a good selection of tequila based alcohol but I just went for a beer
Cabin crew: Disappeared after serving the drink, it seemed that they were serving the same offering to the economy cabin.

Overall: In my own view on a domestic flight, at least at an airport with no lounge (which their website implied was a fair proportion of Mexico) the overall offering was very poor and you'd be better saving your money - I'd have been happier if they'd offered the cabin a second drinks service to at least be a little better treated than economy. However to switch this around - as an economy flyer I suspect the service would have been reasonable and the seats quite comfortable.