Interesting and informative discussion. The Fishman Matric Natural II is my choice but I think all acoustic pick-ups should be carefully matched to the guitar and the player; Body size, playing style etc. The acoustic centre in Wapping, London are the most helpful people when it comes to this advice (that I've found anyway)
I've heard brilliant things about Ashworth too (friendly people, prompt return of e-mails etc) but Phil Beer reckons that although great sounding they can be unreliable and his breakdown an awful lot. Having said that Show of Hands do tour relentlessly so it's probably more usage than normal.