I'm sure this topic has been done to death elsewhere - even on mudcat, probably - but most people say go with K & K pickups. I have done that myself with 4 instruments - 2 mandolins and 2 guitars - and have to say that the guitars do not sound quite as "natural" as the mandolins - although I am using a standard DI, not the dedicated K & K preamp, which might perhaps improve things further.

My best sounding amplified guitar is a 45-year old Martin dread in which I fitted a hybrid (mic + piezo) blender around 20 years ago, made or endorsed by Dana Bourgeois (no longer available of course). I use the mic/piez blend at around 50:50 which is as high as the mic component will go. I imagine similar, more recent blender systems made e.g. by LR Baggs and similar probably sound good as well. Just my 2 cents... - Tony