I'll start off with the cons:
- They are large (not suitable for smaller heads)
- Hard to drive (600Ohm will do that)
- May be uncomfortable for long periods of time due to relatively thin pads
- Non-detachable cable
- May sound shrill to some because of bass roll-off and bright treble
That's the cons. That's all of the cons.
I've heard headphones above and below these in price, but none have matched the open, precise soundstage, clear definition of sound and sheer amount of detail in these beat up old cans. The cable died a couple of times, the pads had cracked due to age and were replaced. When I replaced them, I tried to find something as close as possible to the originals, to preserve the sound signature. They are still uncomfortable for long usage and I still don't care.
If I would ever consider writing a love letter to a pair of headphones, these are the ones. I probably wouldn't have the heart to tell them they have any cons, and certainly wouldn't start with it.