The Seymour Duncan Woody is one of a huge range of acoustic pickups by many manufacturers, and it stands out in its field for two simple reasons: ease of use and sound quality.
It's not the cheapest or the most expensive so it is pitched somewhere in the middle, but it is reliable and simple. It clips into the sound hole with a clever mounting system that uses soft foam to hold the pickup in place - it stayed perfectly where I wanted it to every time it was used. There is also plenty of cable so on stage movement is easy and unencumbered.
The Duncan Woody outputs a very clear acoustic tone through the PA system or through an amplifier. I've used it with dreadnought and jumbo guitars and it faithfully reproduced acoustic tonal qualities of both. There is an impressive lack of noise too; this is a very well made pickup. It is still a single coil so can feed back under gain but that's a very rare occurrence and to do so would be more likely user error than the pickup's fault.
On the whole this is heavily recommended for the honest working musician - I've used it for many gigs and I'd happily do so again. It's never let me down.