Re: Roland Cube
I usually used the Line Out to the mixer. The sound guys love this feature. It has a decent cabinet simulation and it helped spread the sound better.
But I never lacked power and for rehearsals it was powerful enough on it's own.
And if you want to be safe, buy a cheap cab and use it as an extension.
Also, I know this will come as a unbalanced Cube lover or something, but a friend of mine had a Vox VT120+ (twice the speakers and twice the power rating) and IMO at high volumes it fell apart tonewise compared to the Cube.