And it's a shame that they don't accept Diners Club in those programs, which often leaves me wondering if the restaurant is an airline DALC or Diners program and which credit card to use.

The difference is 10 miles per $ for DALC, but Diners coughs up a 20% cash back rebate. The number of restaurants in the Diners program is smaller as well, but all it takes is a $400 business dinner and you've paid your annual fee.

Another nice point for DALC: while the rules state otherwise, I've been able to use coupons and still get the miles, which is nice for the neighboorhood joints I visit frequently.