I have no headphone amp/soundcard for PC/DAC/X1 etc.
Just a cheap mp3/flac player, laptop and a Yamaha RXV-475 AVR/PS3 for Films
Q. Would it be a waste getting such a high end product, I would use them for Music-some film watching. Is the build quality good?
Q. I can get the AKG 551's/AKG Pro 612's for much cheaper, has anyone heard them all?
I own K702, K500, and until a few weeks ago, K612. Given your application and source material, I'd strongly suggest the K612. It's the most forgiving out of the bunch and would be a better match for your receiver. Good luck.