Congrats! Yeah, they are a good headphone for someone not looking for a lot of bass. Good sounstage, too

I own K550 and K702. I don't think a realistic comparison can be made between the two, aside from tonal balance. The degree of refinement is almost Herculean in scope.

The AKG K550 is very light and you can listen to it for hours without fatigue...also it sounds less artificial than the Q701...the pair I own is one of my favourite headphones...I use it with my mac mini but also with my Bakoon HPA-21 don't hesitate to buy it 

I have sold mine AKG K550. Dumped or not, burn-in or not, was the same crap as Sony MDR-Z700 or AKG K272HD. Unforgivable lack of clarity, because of some sort of strange (I think) distortion (stiff diaphragm resonance or reflected wave?).
K701, K500, K501, K401, K240, K140 sound fabulous in comparison to K550. I bought K550 heavy used, so burned-in and I hated it after first second and my collogue reaction was the same. Another pair of K550 and opinion was the same. Mediocre and non-audiophile headphones.
 
If you want to hear the difference, you should use simpler, but more direct equipment: simple current A-class buffer as headamp and old multibit DACs in NOS, non-op-amp configuration. Almost any head-amp and DAC/CDP with op-amps and OS is a crap too, and every pair of headphones will sound similar in matter of the quality (not the signature).