Pros: Well built, pleasing sound signature, lots of accessories, won't break the bank, socketed opamp allows playing with the sound
Cons: Could use more battery life
See full review here: http://www.head-fi.org/t/568054/review-audinst-amp-hp-portable-headphone-amplifier#post_7697280 In summary, this is a great sub-$200 portable amp. It's like Audinst took the already nice sounding amp section of their HUD-mx1 device, improved it by maybe 15 or 20 percent, and then made it portable. What's not to like about that?