I bought this guy with some great expectations and they all were satisfied, with some astonishing surprise.
The cutting-edge design allows for it to be easily stuck on any kind of device (giant, big, long, thin, tiny, small, thick, resonant, smudgy, dull, solid, wobbly and more!)
Sound quality is no-compromisingly superb in that handling noise is zeroed, as well as noise floor. Spectrum is flat, gives a really natural feeling once you hear back from it. It really let you hear from the inside of any device. Maybe works TOO well? Don't think so.
That said, the only bug in the cup is that since it has no pre-eq it comes as an extremely sensitive mic, that means you better place it carefully when you're dealing with consistent bass frequencies that might easily bring annoying physical distortion on the unit (no post HP helps here), ruining your recordings, with almost no-way back. So, find the sweet spot even before pressing REC ok?
And now... The breakthrough: This device is capable of detect ELECTROMAGNETIC FIELDS! You know what that means? Perhaps a little risk of re-introduced hum (it doesn't have on its own) but a whole set of creative opportunities (e.g. try to place it next to smartphones or monitors... Yes, you know now!).
So, in all aspects, a great unit. Highly recommended for pro-recordings. Not the best choice if you're on a budget.