I'd pick the airline with the most flights out of your homme airport. Go on their website and determine the various status levels and the earning requirements. You should also inquire about a status challenge. Finally, you may want to consider a lounge membership and see if your company will pick up some of the cost since it will save you on meals. The worst place to be on the phone with a client is a crowded gate area.

Right now both AA and DL are heavily monetizing first class. I'd check upfare offers and pay out of pocket if it's reasonable and makes sense.