I don't write a lot of reviews, but felt inclined this time because this is one seriously useful microphone! I play several instruments - guitar, Irish bouzouki, mandolin, bass... The thing about acoustic instruments is a magnetic or contact piezo pick up never quite sounds right. Sure they'll amplify but even my tin ear notices frequencies that are lost in translation.I'm also an instrument builder - ok they're cigar-box and whiskey box guitars and ukuleles, but they're fun! I make my own pickups too but sometimes a microphone works best. I began experimenting with permanently-installed mics underneath the box lid - or resonator cone and had a lot of success.The bottom line is - a mic works best for acoustic instruments. The Audio-Technica PRO70 is a great mic and the most massive benefit is versatility. You can slide it off your guitar and slide it on your octave mandolin or bouzouki - even your fiddle - during a gig. And you'll get great sound, too.Is it the best mic out there? Probably not, but it's good enough for so many applications it's a bargain at twice the price. And you don't have to be rooted in front of a mic-stand!SooooBuild quality: Seems solid. Battery pack is sturdy and the cable connection between the pack and mic wire is stout.Sound: On my Irish bouzouki/octave mandolin it sounds great. That instrument doesn't have a lot of bass frequencies and if you use a mic on a stand or a piezo disc they are virtually lost. By putting the mic on the instrument all the precious few bass waves are caught. I tried putting the mic inside the body of the instrument and got more feedback when I cranked it up and lost some treble. On the outside it sounds great. Sound reproduction seems dead on. Granted I've never used a $1000 mic for a live performance, but I wager the difference between this mic and a top-end mic is little enough as to not matter for the vast majority of players.Value: A bargain. Cost-to-benefit ratio is huge. Glad I picked a winner this time. I would (and will) buy more.