Although I am not a frequent DL flyer, I have amassed 150K+ miles with them over the years and agree that they are far above others in both timely and accurate postings. This includes things like my quarterly Schwab account bonus (now being phased out), credit card miles/bonuses, and the recent bonus with AMEX MR (posted almost 8 weeks to the day, as DL promised). I have also had good experience with AA and pretty decent with CO. US has a few problems from time to time particularly with on-line booking bonuses. UA is the absolute worst. I have to call them about almost everything except your basic flight miles. Just called to get over 17K miles in bonuses for the recent DC Double promo and missing on-line booking bonuses. They still owe a few K miles for surveys, some dating back to January. The best of course, is on my recent statement, received this past week for activity thru only April 16 (my DL statement showed up too - it goes thru May 31). The post on my UA statement was for an on-line booking bonus from April of 1998!!! UA should be embarrassed by their almost complete incompetence in getting mileage posted. To add insult to injury, they also owe me 5 paks of upgrade certs. I called to ask where they were and all they could tell me was they were being processed but they had no idea when they would go out.