Bought these off of sonicelectronix.com on a whim. Read a few reviews a while back and figured I'd try them out myself. So far I'm pleased as long as I remind myself they were $20.
Overall these are pretty good, having a decent sound quality. I have had headphones that I throw in the donate bin as soon as finish the first song. These are not them.
As far as sound quality goes, I was initially underwhelmed. The bass was decent, a little punchy. The mids and highs are recessed. If I listen for them I will hear those really low notes a subwoofer plays sometimes. The mids and highs are there, just kind of distant. It does sound clearer with a higher quality source though. I have a 320KB MP3 of You Got to Go remixed by Seven Lions that I'm listening to now on my PC (at full volume and this PC has been able to drive every set of cans I have loud enough, even the ATHM50s I have), and I'm enjoying it. The highs are still slightly recessed, but the mids have stepped closer to their rightful spot, without losing bass. Those subwoofer notes can be heard naturally, but are recessed.
For volume these get loud enough. If I turn it up, it hurts my ears before they distort, though they distort a few clicks up from the amp from there. I have a LG Nitro HD I use at work with Pandora, and with these I keep it around half volume. My phone has, in my opinion, a lousy amp, so on max these phones get loud, but not nearly too loud.
Built quality is OK. everything is plastic, but it feels like hard plastic, except for the headband, which feels a bit more flexible. Not a bad thing considering it needs to fit many sized heads. My head is rather large, but these fit well without getting uncomfortable. I wear them for up to three hours at a time at home. The cushions do feel a bit plasticy, but after about 10 minutes they become softer as they warm up. Cord feels rather strong. The rubber sheath feels like the cheap kind, but is thick to make up for it. One wire goes into each cup. I bought the blue set and I like the shiny blue exterior on the cup with the word SONY in chrome. The cord length is short though. My regular (and quiet) PC Is 4 feet away an if I lean left past a 35 degree angle it pulls tight. A bit frustrating, but I have a set of Panasonic RP-HTF600 that I wear normally that have a longer cord. There is a red indicator on one side that notates the right side is that one. Makes it easier for me.
Isolation is good for this type of headphone. These are on-ear and closed. As soon as you put them on, ambient sound like A/C is gone. I, however have a PC with several 80mm fans 4 feet from me and a glass front minifridge 10 feet from me that make a considerable amount of noise. At about 20% volume these are no longer heard. Someone knocking on my door won't be heard after about 60%. I can use these at work at about 30% on my laptop without anyone hearing me. Not bad at all.
So in closing these are a good value for the price. Pick em up and give them a go.