That extra space for ventilation isn't bad. I've heard amps tend to overheat in rack bags ...
I've always had mine in a Protec 3-space with no heat issues.
I prefer the bag overall because it seems to offer a bit of shock protection and I don't have to fret over scratches in the plastic of a rack case.


M6 Master Volume is set at 8 O'clock, Input gain at Noon. Bass EQ flat, Voicing 3, Mids at 10 O'clock, Treble at 10 O'clock.