Don't see much hoopla around here regarding these.  There are some reviews on Amazon and few here and there on the web.  What fascinates me about them is the dual drivers.  40mm for bass and 30mm for mids and highs.  Seems like this would be a great advantage over traditional single driver portables.  Price is right too... $50 to $60 online.  Here is a link to Pioneer's website with the specs:
 
http://www.pioneerelectronics.com/PUSA/Portable/Headphones/808+SE-MJ751I
 
Perhaps the Pioneer name doesn't command respect like say Sennheiser or [insert your favorite brand here].  I'm thinking about giving these a shot.  Comments?
 
Edit: here is a pic...
 

The advertising is exactly opposite of what I want in a headphone. But that's me, I am sure for others this will be right up their alley .

if you think these are worth a try I say go for it and be sure to write about your findings here so others can benefit.

These are decent headphones. Bass hits hard but don't really go low enough for me. For some reason the bass gives me a headache. For a few bucks more the HDJ500 is a much better pioneer headphone.

There's a thread about this headphone on Head-Fi.  Outside the US, the headphone goes under a different name, but it's the same.  It's actually a great headphone for the price sonically.  Bass is adjustable and overall the headphones sound great.  The largest issue may be treble that might be a little edgy.  Definitely worth a look for 50 IMO.