re: Best beginner acoustic guitar for an adult

I've owned a lot of guitars, I prefer traditional, non cutaway guitars so those are the styles I've owned and played.

Yamaha if you're going under $500, specifically the Yamaha FG830 is a great value. I learned to play on this model.

Eastman if you're looking in the $600-$1200 range, you can get a nice, pro level guitar at the top of this range that will go toe to toe with the Martin standard series.