I fitted one of these to my 15GS last weekend. I am in Australia, we have a local distributor and it cost AU$256 / UK156.
Very easy install and works right out of the box defaulted to Config 1. You can turn the lights on/off by pressing the indicator cancel button for 3 seconds. Left toggle the wonder wheel for 3 secs then use the WW to dim or bright the lights, this setting is saved for each of the low & high beam settings.
Connect the laptop and you can change the config, I left it on Config 1. This is 10A each for the first 2 outputs, my lights draw 3-4A each so I set the fuse to cover 1 & 2 @10A. you can then set the brightness per output for day and nite in low & high beam. There are options to turn the light off when indicator on, Alt flashing to hazard lights, strobe with horn and high beam flash.
The 3rd output is rated at 4A and is intended to be used as a secondary brake light like an LED strip. It has settings for flash on brake or deceleration (no brakes). The 4th output is also rated at 4A is intended to be a AUX power line for USB, GPS, etc. The overall current output of this device is rated at 28A continuous and it can handle spikes >28A for up to 20 seconds before popping the fuse.
Overall I rate this unit very highly for quality, ease of setup & use, the additional connectors and cables to allow you to connect all your devices, the features and the price.