I've used Amex travel before, but not for AS tickets. The main reason to use them is (1) the IAP program (discounted international tickets on several major non-US airlines), and (2) they have discounted AA tickets. I believe you need Amex Plat or Centurion for either of these.

In my experience they are fine if you are just going to fly the ticket as booked. I was able to enter my FF number and get my expected benefits. If you want to make any changes it may be a hassle.

If you want to change the ticket you must go through Amex. The airline won't touch it. Some airlines may offer to "take over" the ticket, probably for a fee, possibly waived for elites. I'm not sure if AS can or will do this. AA was not able to do a SDC or take over my ticket, but I was told that that was due to their contract with Amex over those discounted tickets, so I'm not sure if that would be an issue with AS.

If your flight is cancelled and you are due a refund you probably will need to deal with Amex. If there are irrops and you need to be moved to another flight, the airline should be able to take care of it.

Personally I would transfer my amex pts to an airline and book award tickets. You will get much better value and won't have to deal with this mess.