As a regular on AM 668/669, let me try to stick up for AeroMexico a bit:
- You need to remember what you're comparing their service to. Other flights Bay Area - Mexico are either not going to have an F cabin, or are going to have a dated US3 domestic F offering. Aeromexico's 737s consistently have footrests, IFE, and fast WiFi. You can get those on UA/DL/AS, but that's not guaranteed. On Aeromexico, it is. (Similar argument for their 788 JFK-MEX service--yeah, the cabin isn't the best, but if the alternative is Volaris...)
- Flying through MEX T2 is infinitely better than MEX T1. At MEX T2, at least the arrival hall is well-ventilated
- You get access to the Virgin Atlantic lounge @ SFO, which is far better than whatever other lounge you'd get on a competitor (UA interim RCC? DL T2 SC?)
- Soft product is definitely an area for improvement (next time you're re-insulating your house, consider AM's "fish" meal), but I find that--if you address them in spanish--the FAs are comparable to what I usually get in DL F