It isn't about being flawed or more accurately less flawed; it is about fit for purpose and different likes, dislikes and preferences. Some fons are forward and agresssive (Grados) others have warmer sound sig (Senns), some are detailed and/or emphasis on highs, etc etc, and then there is closed, open, and then there are the comfort issues, and then there is durability (seriously fell apart after 1 month?) and other parameters (like asthetics).
Which headphoes are less flawed is simply another way of asking which are best. And that is a highly subjective question. Which car is best? Two seater sports coupe, or four wheel drive seven seater; V8 or turbo charged 4 etc etc. @ $500 or thereabouts, it isn't about which is best, it is about what suits your preferences. The OP needs to identify what is important to him, and then get Headfiers opinions on what might be the OP's holy grail for $500. I like my Proline 550s and I like my AD900s, but they are very different fons based on sound signature.
Cheers and good luck with your headphone journey. And just like life, it is the journey that counts, the destination may not be all it is cracked up to be.