the piezo sounds, well like a piezo - although better than the last one i had. useable sounds therein, and a great mid-range EQ band. i bought this guitar primarily to play live with, probably via a PA. i am thinking about getting one of those fishman pedals to soften the piezoness of it, have seen some demos and they sound really nice. the onboard tuner is great - exactly what you need when you have had a few guinnesses.
i tried it though my twin and it sounded awful, but through a line 6 tone port on my PC it sounds super. guess you really need an acoustic amp. i'll record some stuff tomorrow with it when i have tuned the EQ to the sound i like.
as for the yamaha thing - yeah, i bought this as my friend has a folk size one from the 70s and it is amazing.
the build quality and set up are first rate, for a guitar this price you get a lot for your money.