which metronome? metronome/tuner?

[bassbounce]

I need to buy a new metronome and am deciding between the Korg MA-30 (metronome only) and MA-40 (tuner/metronome).

I understand that there is only ONE volume level when using headphones with the MA-30, and it is only mono. Does anyone know if this is true with the MA-40?

Also, is there any disadvantage to using the combo tuner/metronome? I won't be using this onstage so it seems like the simpler option.

Thanks.