I'm assuming I'm in the minority here but I think I like the group stage more. Don't get me wrong, I enjoy the QFs, SFs, and Final. I enjoy them a lot. But even though the teams are usually elite they can often be games that are not as fundamentally entertaining. Finals especially. Sometimes they are just crappy games because two good teams are scared to make a mistake with the stakes at hand.
Yes the group stage is not as high stakes and includes a lot of lesser terms. But the lesser teams are still usually good enough to keep the games interesting. And the sheer volume of having 4 games a day for nearly two weeks is amazing. In my mind, the drop off in qualify from say, a QF or SF to a random group game is more than made up for by the sheer quantity of games during the group stage.