This cab is everything that I need for trying out speakers. Purchase speakers of the right Ohmage and experiment to your heart's content. No need to solder anything so it's a 5 minute job to change speakers.
It also sits a Marshall Studio Head on top perfectly.
This cab enabled me to discover that a vintage Marshall type head rocks harder with H magnet speakers than M magnet/greenbacks. And that the two together is a perfect mix. And that a Vintage30 and H are also great. And that a standard Greenback and an EVH sound different. And an 8Ohm and 16Ohm also sound different.
Stick two speakers in the cab, set it in Stereo mode, match the individual speaker impedance, not the total, and then switch the cable from one input to the other, utilising the amp standby switch, and quickly compare two speakers.
I also find that using two of these cabs is easier than having to transport a 4x12.