Summary: Great sound but poor production quality.
My Fishman Rare Earth Mic Blend arrived with empty batteries. No harm done. This can happen. After changing the batteries and tweaking the microphone position and the pickup/mic blend to my liking, I ended up with a great sound.
However, I again ended up with empty batteries a week later, while hardly having used the guitar (and having left it unplugged when not using it). After measuring with an ohm meter, I discovered that it was using battery even when unplugged. After careful examination, I discovered that the connections on the output jack were very badly soldered, and that the red wire was soldered on the outside of the connector pin, and as a result touching the metal screw-on cover sleeve. I was quite tempted to send the product back because of this poor production quality, but since I like the sound, I ended up fixing the problem with a small piece of electrical tape to protect the red wire from short circuiting against the screw on cover.
Positive: Great sound
Negative: For the price I paid for it I would have expected much better production quality.