I have a TS rubi cutter which has a limited range of uses, not a recommended purchase.
Sigma cutters are nice, I just used a buddy's Sigma for some 2 inch mosaic and it cut really nice.
But...
Our next cutter will be a Montolit MasterPiuma.
I like the looks of the rubi, and Sigma seems to be good gear, but montolit has some nice features that has me inclined to go that way.