Interestingly enough, I find DL's site really quite good for booking basic domestic tickets----out of 15 or so I've booked over the past month, today is the only time I've had a problem (the repeated 'just sold out' problem), but the DM line got the issue taken care of immediately. I sure like DL's booking engine much better than AA's for domestic flights. What needs a lot of work is the award booking function, for which situation I'd call the DM line and not even attempt it on-line anymore....