Guitar Nerds Anonymous

I've tried a few.

Fishman Neo-D – cheap, got one for my godson, simple, discreet, really pretty good, 7/10 overall. On a tight budget, I'd say get one
Fishman Rare Earth humbucker – currently using one, a bit spendy and rather bassy but reliable and EQ-able, 8/10. Single coil is cheaper, dual-source Blend versions with internal mic not worth it IMO
LR Baggs M1 - available active or passive (needs external preamp), toppy, Stratty-sounding unit, picks up soundboard vibration but also clicks when you hit it with a pick, loved mine at first, don't anymore 6/10
DiMarzio - mostly not much cop, but the discontinued DP-139 is brilliant, 9/10. New Angel model will be worth a look
Dean Markley - pretty average, 5/10
Shadow, Seymour Duncan: haven't tried any of them
Sunrise – heavy, expensive, needs own preamp, 7/10
Fishman Blackstack, copy of Sunrise, heavy and very electric-sounding 6/10

As you likely know, well-sussed EQ is the key to getting all these to sound good live. I never trust sound engineers with acoustic, I always ask them (sweetly of course) to set the desk flat and then set my own EQ with a little preamp on the floor, usually mostly cutting a shitload of mids.

I have a dean markley "woodie" you can have for not much if you're desperate. it's good in an emergency and definitely not good for much else.

after a lot of research i got one of these for playing my acoustic live. http://www.kksound.com/acousticguitar.html love it. sounds great and it's totally invisible. highly recommended.