Pros: Portable, improved sound over your source be it phone or MP3 player
Cons: Altoid tin case
I use mine at home and at work during breaks. The 9 volt battery lasts forever (a long time anyway!). The amp has plenty of power to drive full size phones. Volume control is smooth and easily controlled. The Bass boost switch works, but if you need it for your headphones get better headphones. The bass boost is over powering and leaves the bass muddy with phones that have decent bass. With bass boost off and good phones he sound is clear, soundstaging good and there's no background hiss. Using a line out cable from my I pod to amp the whole rig will still fit in a shirt pocket and sound quality is greatly enhanced/improved over the I pod's headphone output. Build quality is good with neat soldering and a snug fit in the tin. Well worth the price and a great way to get started wit this hobby/obsession.
After posting my initial review I received a message from a representative of JDS labs letting me know they could customize my amps bass boost! Specifically they offered to darken the bass boost since I had characterized it as "muddy"I will send off the amp soon and revise my review when I have a chance to listen. The ability to customize the amp makes it an even better deal!