Pros: Great sound, good bass, balanced lows, mids, and highs
Cons: Long Cable
These things are amazing! After about two hours on burn in these really shined. I own a 1500 dollar pair of Grado's and the Seinheiser 650 (both great brands), and these M50s compete with them. I honestly would of never spent that much money on headphones if I tried these out first. Very durable.
Which model Grados? I see you haven't listed them - or the HD650 - in your profile, yet you've listed the M50? And what amp and dac combo were you using for the mystery Grado, and also the HD650 (you have no amps or dacs listed)?
Just my opinion - as I've spent time with the HD650 (own the HD600) and also the M50 (which I never really rated that highly) - and IMO the M50 is not even close to the same class as the Senns.