That was probably me. I read something in the manual about the Mid control affecting the 'feel' of the amp more than the actual midrange content, so I tried it. AWESOME. It brought out the best in the speaker, worked with all my guitars & pedals, and just in general made a great amp better. I keep my Mid between Off and 9:00 on both channels, and definitely don't lack for mids in my sound.
This would not be the right setting if you like a hard, ultra-snappy response. It seems to slow things down a bit and create a squishier feel, which I love.
As for the bass control, turning it all the way off makes no sense to me, especially if you play single coil guitars, but lowering it down to 9:00 or so is great for making humbuckers less muddy. Why would someone roll off all the bass?
Hope that all made sense!