Im new to the tiling profession and i use Sigma also brought myself the mini montolit for the little metro tiles which worked out better than i thought.
Got to say I've had Rubi all my life until tiles got bigger and thicker. I then moved onto Tomocanic but they went bust when I needed a new big cutter.
The Siri Pro range is the best I've had. Nicely built all metal construction and almost every part is replaceable.