I asked this question a few years back, almost caused a meltdown.
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I finally lost patience with my Rubi TS60 Plus on a recent job, only cutting 500 x 250 porcelain tiles. Needed 32 tiles to tile a shower, with 16 of them being cut across the short edge. Looked like a straightforward job. Long story short, I had 8 spare tiles and all my spares were used up with the first 8 cuts at which point I had to switch to my wet cutter. The Rubi just will not break tiles cleanly along the score line.
So I did my research on this forum and finally plumped for a Sigma 3B4K Klick Klock. What a difference. The breaking system (which I honestly believe is the problem with the TS Plus series) is superb. I've been practicing on loads of spare left over tiles just to see what it can do and I even managed to snap a 12mm sliver off a 600mm porcelain tile just by taking my time with the breaker and moving it up the tile bit by bit. Incredible.
As yet almost every tile I have practiced on has snapped on the line. This machine is just excellent. Wish I had got one years ago...
I'll still keep the TS, it's great on ceramics with a fine wheel, but regarding the Sigma v Rubi debate, I think I'm firmly in the Sigma camp...
ps Thanks to all of you who give advice on this forum, it's been invaluable and much appreciated.