I have a Fishman active UST in my Lowden. It's OK, but it suffers from the usual UST drawbacks.

I had a K&K Pure Western Mini bridgeplate transducer (passive) fitted in my Martin which is far, far better - very 'natural acoustic' sound, no quack, plenty of gain - I seldom need to use my Baggs Para Acoustic box, usually just plug straight into the desk for a great sound. About £100 fitted, at Vintage Instruments, Norwich. Never regretted it.

And I agree with someone else's comments about using EQ boxes such as the Baggs or Fishman, they often need a lot of work to get the sound 'just right', and it's easy to bugger your sound up instead of improving it. IME and IMHO.