Didn't we just have this thread? Oh well...they are still as good an airline as they were then. The whole experience on the ground is very pleasant..., on-time departures, electronic check-in options, lots of employees to assit, good baggage handling etc... They also have an excellent frequent flyer program, with loads of partners.
Once in the air, the service is good, for a US carrier. The fleet of 737s and MD-80s are the among the youngest and most modern of any domestic carrier, and they are clean and attractive inside and out. Seat pitch is not bad. The F/As are typically friendly and efficient. Not really any in-flight entertainment, but they are looking into a really cool live satellite TV system (doing a test run of it in March). Meals aren't huge, but they are usually very good.
I guess that basically sums it up. I certainly wouldn't hesitate to recommend them to a friend.