Sorry off topic ... I use an Electro-Voice RE27ND or a Shure SM58 and an XLR to USB2 from M-Audio and get good results from GB (as well as the higher end apps). I never used a USB mic so no idea what they are like to be honest. (Not that you said you used one ... just commenting on that).
Hey thanks Digital clips! Good to know!
Sorry guys for being off topic!