Thanks... The store where i'm using the card doesn't accept American Express....
Ok, spg is no good but the first part still applies. What do you value your miles at?
A simple example, 2% back on $25k is $500. If you use your miles for domestic travel then take the cash and in most instances you'll walk away with change from buying any domestic ticket. Plus, you earn miles on a paid ticket which is worth money.
On the other hand if your miles are going towards international travel in premium class the miles are going to be worth many times more then 2 cents (2%).
Its really up to the individual to decide.