I've flown them 15+ times, about 3-4 trips a year for the last 4 years. TJ > Uruapan direct.
they are a discount airline. everything is an cost+ add-on. I don't book the tickets myself so I don't know the specifics. And we always pay the extra for exit row for the extra legroom.
If any other airline flew into Uruapan, we'd probably jump ship.
customer service is not very good. we just got screwed out of a $500 round trip ticket because the ticket was booked for "Doug" but his passport said "Douglas". they wouldn't let him board the flight. had to buy a new ticket for "Douglas". tried to fix the return ticket to change it to "Douglas" but they refused, kept trying to say that you can't change the ticket for a different person. couldn't/wouldn't understand that Doug was short for Douglas, like Max could be short for Maximilio. They said that "Doug" never showed for the first flight so no refund/credit on the first flight or the return flight, even though he was there and they just wouldn't let him board.. had to buy a return ticket under "Douglas" so he could get back home.
We'll see what AMEX has to say about a refund.