To our ears, the differences between the Sr-60 and Sr-80 models may come down to the differing earpad design.... in other words, they both sound fairly similar overall imho.
Given that the HeadRoom "value rating" system is weighted towards the less expensive stuff that performs well at a low pricepoint (...of course, we all expect the pricey stuff to rock!), the $69 Sr-60 receives higher value marks versus the $95 Sr-80; the Grado Sr-60 may actually represent one of the better bang-for-the-buck headphones in the industry
Cheers,
Jorge
HR Sales/Product Manager