I'm extremely glad I purchased the Midi-Expander, and any negative feelings I have towards it are more about the principle than anything else.
In short, the Midi-Expander allows you to plug your SoftStep into a DIN MIDI device, as the SoftStep itself only allows for USB MIDI connections. It also allows you to power the unit without it needing to be plugged into a computer.
Now my concerns here are that SoftStep itself is quite a pricey piece of equipment, and to have to pay another ?44 to be able to fully take advantage of the device's capabilities seems a little bit on the cheeky side to me. I say this because there is almost nothing to the Expander, it's a flimsy little metal case that has almost no weight at all, with a couple of sockets in the front. KMI, I truly believe you should have bundled this with the SoftStep.
It's hard to rate this properly: it serves its purpose perfectly, but its construction seems so cheap and flimsy it could have come out of a Christmas cracker.
4/5: Necessary, but too expensive, and for what it is it really should come bundled with SoftSteps.