I own all of them except the HD-428. I would say the DHP-II.
You can however change the DT-235 to make it surpass the DHP-II in sound and comfort.
What you do is take the DHP-II pads off and put them on the DT-235 to make it circumaural from supra-aural.
You've now got the most comfortable headphone there is, but it has too much bass (but not with the default pads!). You can now mod it to bring out the mids and remove the bass bloat. It involves putting masking tape over 2 of the holes behind the driver and adding some blue-tack.
My DHP-II is out on loan, but the DT-235 when fully modded does probably sound better than the DHP-II.
DHP-II is now somewhat hard to find and it's price is too high. If you can still get it for under $50 it's worth it.
I wasn't a super huge fan of the DT-235 until I modded it. The mids are really nice when modded.
The UR-55 is nice, but the sound isn't as clear as it could be and for many it's not that comfortable.
BTW many Sennheiser pads can fit on the DT-235 to make it over the ear instead of on ear. HD-497 pads do and they're cheap online. The pads are under $10 online.
More people should mod the DT-235. I posted a thread about it and it's quite good for $55. It's even good for gaming!
Quote:
Out of these 4:
- Maxwell DHP-II
- Sennheiser HD428
- Beyerdynamic DT 235
- Koss UR55
Which one would you guys choose based on sound and comfort?