The M1 consistently generates heaps of praise for its easy installation and great tone. I've installed a number of these as well as using them onstage, and I can report that the buzz is totally justified—this pickup rocks. It's a magnetic soundhole pickup, similar to the Fishman Rare Earth, but its tone is remarkably acoustic for a magnetic. The tone is no doubt helped by its individually-adjustable pole pieces, which let you adjust your string-to-string balance. 

While the passive M1 is best paired with an external preamp like the Para Acoustic DI, the M1 Active listed here adds an internal battery and preamp, eliminating the need for external preamps, all for only $50 more. The Active version also features an onboard volume control.