A big 10-4 on that last observation, Greg.
My experience has been very poor, but almost exclusively involving AA. Note well, however, that you'd expect my experiences to be with AA, because they dominate DFW.
AA operates under the premise that, if there is a significant WX event at their primary hubs (DFW, in my case), they pretty much schick-can the entire schedule and start over the next day - and as harsh as it sounds, I cannot blame them, since there are only so many crews available, and if they all time-out trying to fly to someplace they just can't get, then where are you, and your pax?
Where they fail miserably, is in the reaction at the terminals to these cancellations and disruptions. AA follows the mushroom theory - keep 'em in the dark! I have experienced this at SNA (I mean, for the loveaChrist, you cancel a 757 going to your largest hub and have no contingency plan to handle all the people who need to be re-routed, no agents dedicated to this issue? While I waited in the huge lines, three planes which could have gotten us home left with empty seats, and I ended up having to buy $1150.00 worth of seats on America West to get home), at SFO (had to find my own way home on UAL) and at BTR (four of us drove home in a rented Hyundai). AA pretty much closes up shop and leaves you to your own devices. On the other hand, when there are WX disruptions on SWA, they have teams of agents who go to the gate areas of the affected flights and aggressively work to re-route pax. Huge difference of attitude and approach. I cannot comment on other airlines, as I have no experience with them (well, Braniff used to do a good job, and AeroMexico put a plane load of pax up at a hotel in Monterrey...).
On the other hand, on the one diversion I have experienced on AA (FLL-DFW), the cabin and cockpit crew were exemplary, exhibited the very highest in courtesy and professionalism, kept us fully (and accurately) advised while on the ground at San antonio... then, when we were finally able to get to DFW, we had to sit waiting for a ground crew to marshal to the gate for at least 45 minutes (how must that be for the cockpit crew after a LONG DAY - looking at the gate, 50' in front of you, and knowing you can't just go on up...