I've had a pair of HD280s for several years. I do not hate them though they wouldn't be my first choice for a friend.
They are still my go to headphone for practicing guitar with a headphone amp.
My biggest concern may be a strength for some people... I do not find them comfortable. Neither initially nor after prolonged use. If I am looking to kick back and listen casually for a couple hours and perhaps even doze off, I would definitely not choose them.
Having said that, when playing guitar, esp when learning a song, I'll often look forward, then down at the guitar, then at the comouter screen or tablet or what have you. In that capacity, the headphones stay firmly in place.
Also worth mentioning, I've had these for about eight years, they are often thrown in a bag or very rarely shoved a gig bag. They've been abused and they are still 100% going strong.
I put the HD280s, the 7506/V6 and the ATH-M40s in the 'quite flawed, but a solid choice' category. They are each extremely popular and work for tens of thousands of people, are pretty reliable, don't sound horrible, don't require an amp, are affordable and other than the Sonys aren't fatiguing sounding.
I just think that, for me and for people wanting a more comfortable, less colored and more musically versatile option, there are better choices these days. Esp on the slightly used market.