Around 3 hours is perfect in my opinion. Long enough for it to last a good while, short enough for you to be able to listen to one each week. Sometimes I pause it, and if I don't finish it there's always next week.
What's sad is how many games on the current gen consoles are sub 720p. Just because they can't manage to be as pretty as they want to without scaling down the resolution. Resolution is to me the thing that comes before everything else in graphics. But hey, it must be hard to manage making better looking games this far into a generation of consoles.