There's nothing wrong with the AS Visa, it's an excellent product, especially if you fly Alaska even occasionally and can make use of the annual companion ticket.

If you want to use this card, it will serve you well, and AS miles are pretty valuable. Upgrades on AS metal are only 10k each way, confirmed at booking from any fare (provided U class inventory is available). And their miles can be redeemed on BA/QF/CX/CO/NW/DL/AA...

That said, I still like other cards a little bit better. In my limited experience Diners Club customer service has been folded into Citibank's general operation, so its outstanding service may be no more.

And frankly I've found Amex to be better than Citibank or BofA. I have the Plat card, but I've had no problems with my SPG Amex either. I've had to dispute a couple of charges and they handled those instances exceedingly well... better than Diners Club (Citibank) or BankOne in similar situations. I suspect any past disservice was either out of the ordinary or no worse than you'll experience elsewhere.