I previously owned the Superlux HD-660, and I wanted another pair, but they were discontinued. Until I discovered that THESE (the 660 pro) dropped. I ordered immediately to see what they're all about.
These are more of a middle ground for recording/mixing, since they have a tiny bit more bleed.
But the pay-off is big. You can wear these for hours and feel zero irritation. Very soft and cozy feeling on the ear.
They're a tad bit brighter, but they also respond a bit better at the sub-bass frequencies. And also, the original 660s were also giving me a bit too much around the 600-1000hz area, whereas these don't. So, you could say these are a bit more V-Shaped, in comparison.
I enjoy listening to these more, and wearing them for longer hours too. And they're absolutely fine for recording too. The bleed levels are STILL comparable even to the DT-770s.
If you don't wanna spend much and still get a comfortable, great &bright sounding pair of headphones, look no further :)