Well, here in Memphis (Northwest hub) the biggest complaint we hear is the price of the tickets. But for the most part, Northwest has a good record here. I know the first time we flew, probably in '92, the people at the counter were rude and the flight attendants were very snotty. Had we had more choices, we might not have flown them again. However, every flight since then with the latest being this past February have been great. The ticket agents have been friendly and helpful and so have the flight attendants... especially on our flight home when my 1 yr. old got sick... one flight attendant was at my side with paper towels and water before I could even look up. He checked several times during the remainder of the flight to see if he could help with anything. My parents have also used them for years with little to no complaints (also flying out of Memphis). Try not to worry... chances are your flight will go fine!
Kelly