Bought one of the Fine audio units last week, and it is plenty loud. Not much bass, true, but I have an equalizer program on my android to tune the sound profile.
It makes this fairly annoying POP sometimes twice, Pop Pop, and while I am a big fan of Magnitude, this bothers me somewhat. I have not had time to test the battery life yet, or determine what makes it pop and what doesn't.
It will also blip and bloop about the BT connection at times, again this might be my device dropping and establishing the connection.
I don't usually return things, it is just too much hassle, but I will post again about battery life and how it sounds in the car, which is what I really wanted it for.
Overall a good deal for the price, especially if you already have a cart going.