It´s easy to use. Important: do not use with a clean amp it sounds horrible BUT, try it with an amp on the edge of breakup and you´ll get those classic tones, it´s unique.
It cleans well if you roll down the guitar volume, pretty versatile. It doesnt add volume really, just adds those extra frequencies and more grit. I loved into the top boost channel of my vox. It screamed! Instant Rory Gallagher and Brian May tones. IO also used on a more gainy amp and it gets really close to the first Sabbath tones.
The built is good, looks like a boutique amp, which is kinda scary cos you don´t waznna break it but it doesnt look like its easy to break. Also, it´s very light.
Overall I´m pretty pleased.