Pros: Frequency Range, Build quality ( Notes ) , Price of course.
Cons: Blaring Highs, Sound quality Poor is "meh" without equalization.
The MDR ZX100 were in my view at Bestbuy for 12 dollars and for such a price I of course picked them up and threw it in the bag.
Getting to the point, I have had these for a year and the overall quality is ok especially considering the price.
Build Quality - Although plastic, the quality is sturdy, I dont know what the other reviewers are talking about in terms of comfort because there is no comfort loss when wearing these for prolonged time due to their minimal weight. The plastic is no way "cheap" and will not break on less you intentionally step on them to break.
Lows: Hearing the subwoofer shaking lows with this pair is not going to happen, out of the box the zx100's frequency response definitely favors the middle to higher spectrum.
I cant say that bass doesn't exist, because it indeed does, but in my opinion it isnt where it should be. Think of the lows sort of being like that of a cheap Logitech 2.1 subwoofer.
Mids: The mids on these headphones are very prominite and make voices and all the "etc" sounds in movies and songs very audible. This is indeed my favorite part about these headphones is that the music does not sound drowned out and muffled by bass, but instead rather clear if it weren't for deafening highs.
Highs: Okay Sony, I guess.
The highs are hard to explain, its like having a horn tweeter placed right next to your ear at at least 50DB. The highs are extremely defined, and although this isn't a horrible thing it should be toned down a bit.
Overall : Out of the box, these headphones produce okay sounds for your ears, although I can guarantee your for free that it can be worlds better than it currently is.
With equalization, these headphones are truly becoming a grand value. Increasing the 10-60 Hz frequencies solves all sound quality issues with these headphones, it will tone down the blaring highs and the lows will be more audible as they should be. Although the bass still wont shake your head with an eq, it will be more pleasurable than it would be.
Basically, after heavy equalization, these headphones easily make it sound like it is in the 30-60 dollar tier.
Why not get them, They are 12 dollars...