I've had the Megamini for a while, and thought I would summarize the pros and cons of this device.

Form Factor:

Plus. The form factor of the Megamini is an obvious draw, and it is both light and easy to carry. It's multiples smaller than a cell phone.

Battery Life:

The battery life is good - what you can expect for this size - but I do wish HifiMan would have advertised more realistic numbers. I have never gotten 15 hours on this thing, maybe closer to 2/3 of that on a good day. It's a bit more difficult to estimate as I don't let it drain to zero.

UI:

The UI is slow, and its age apparent with how quickly DAP's have developed. It's not terrible by any stretch, but definitely slower than a phone or other, more recent DAP's.

Sound:

I always have some trouble with describing sound - especially for DAP's - but the Megamini's sound is controlled. It delivers enough power to drive most cans that are not power-hungry, but it's like comfort food - safe sound, but not wild or dangerous. It is not muddy either to be sure - it sounds clean, given the headphones you are using are the same.

Conclusion:

The Megamini was a nice DAP for its time, and I still use it. But given the influx of more recent offerings, it's hard to recommend. Still, if you do get your hands on one, its a nice player that goes well with most cans.