Pros: Small size, battery life, Amp for higher end headphones
The build quality is nice, the overall product is light and sturdy. Ive never been a fan of glossy plastics though, they attract fingerprints and just scuff up but to each his own. Battery life is something around 10-12 hours total use according to the manufacturer so this is great for everything, even long flights. There is a nice clip to hang it from your pants or pocket si it doesnt get in your way when you work out.
The sound you get from this little guy is crazy. It has 4 EQ settings (for those devices that dont have one built in ie my zune) The blue light setting is my favorite of the 4, it adds a nice hint of extra bass and mid power. When you compare this to the stock headphones (which were great by themselves) the difference is night and day. There is volume control on the amp as well as the device and with both cranked up all the way my Sennheiser CX 500s were literally vibrating from the sound they were producing. I have shown this thing off to a few people in my company and they are amazed by the difference and thinking of grabbing one themselves for Ipods and phones.
Cant recommend this gadget enough! If you love quality sound, pair this with some nice speakers/headphones and you will not regret it.