Yeah that's closer to how I feel. Idle Thumbs seem to be interested in a wider variety of cultural experiences, film, literature. Giant Bomb have an advantage when it comes to technical stuff, hdmi outputs or whatever.
Idle Thumbs, and this is the biggest thing for me, know how games are actually made (because they all actually make games), and use this to inform their discussions of games.
GB, or at least one or two of them, suffer so badly from some kind of ironic detachment that it makes it difficult for me to put up with for very long.
They both provide an excellent service, and a great body o' work. The persona 4 endurance run alone will always keep GB in a special place in my heart. But for me Idle Thumbs is head and shoulders above all other casts.
I heard that the giant bomb guys went and took some improv lessons to help ameliorate their podcast. As a bit of an Improv dabbler myself I was happy to hear this. Improv is one of the best games there is, when done right!