As with all products, some reviews are critical and some are full of praise. Based on the high ratings and several reviews from pros mentioning how good the sound was, I went the extra from around $79 to get this one, and I love it so much that I shortly bought a second, so I could put one in each of my two beautiful sounding Martin acoustics. I play them through a Roland Mobile Cube (the little short and wide one you can find here), and am extremely pleased with the sound as well as what I can get out of the Roland. It has several choices of effects, including plain acoustic, electric, over drive, distortion, chorus, delay, and reverb, and PLENTY loud enough for the small place I live in; even better with phones on!Mounting tip: You can probably mount it without pulling the strings, unless you want to change them. I had just put on new sets and wanted to keep them on. Just loosen the tension up as much as you can without the string popping out of the tuning pegs. You may be able to reach your arm through the sound hole to mount the output jack; I did on the six string. But the 12 string was more difficult, so after loosening the strings, I carefully pulled out the pin and removed the string, put it aside, then re-inserted in when the job was done.For drilling, use the stepped type drill bit which will drill multiple hole sizes, chucking it (for the Martins) so the drill just catches about 3/8" to 1/2" of the shank; otherwise, the drill chuck will hit the guitar before the drill goes all the way through. You will need to go all the way up to 1/2" hole size. DO NOT TRY TO USE A REGULAR or any other type bit, as you will almost certainly split the wood. Not nice!BE SURE TO PUT TAPE ON THE BOTTOM OF YOUR GUITAR around the hole, so if you do slip, the damage will be limited; and go nice-and-slow, with constant speed, on a the LOW speed setting for a cordless. Put a small bit of Beeswax on the outside of the bit and the cutting edge to reduce friction, "grabbing," and make for a MUCH better cut.Here's the tricky part: find an old wooden knitting needle, wooden dowel, a very long bamboo chopstick, about 14" long. At the business end, you want 1/4" diameter and of course, smaller than 1/2" at the large end. With everything ready, unwind the pickup wire fully, letting the pickup dangle on the table top (hope you put a towel under there), and with one hand put the output jack through the sound hole. Now with the other hand, insert the 1/4" knitting needle, dowel, whatever, through the hole you drilled and up towards the Sound hole, where you will insert it, while twisting slightly, into the pickup jack - the part that will go through the hole. Smoothly pull the knitting needle or dowel, etc, back through the hole (you did remember to remove the nuts which hold it in the hole before starting, right?), and twist slightly to remove the jack from the dowel.This turned out to be so easy that I did it several times until I had the exact length of the mounting nuts perfect. So, tighten down the assembly with your fingers (no locktite, please), mount the pickup in the hole, then shorten up the cord and wrap it up with a Velcro type, multi-use fastener for easy removal and battery replacement. Put the strings back in, tighten the tuners, tune - be sure to adjust the sound level to "high" as the manual suggests - then plug and PLAY!