hi steve
i like rubi too and if you have used them all the time, then i can pretty much gurantee that you wont like the pulling action, especially on a 900mm cutter.
i had a montolit 93p and it was a brilliant cutter. 600 x 600 porcelain on the diagonal were easy as. lovely neat square cuts, tip to tip. wish id kept hold of it so i would recommend that all day long..very light too, so if you lugging it around from the job to your van, then it aint gonna give you arms like a baboon.
as for the sigma max range, they do look like they have addressed everything you need. push cutters are more natural imo over that distance and i like the fact that you break the tile at the your end, rather than learning over. they have also integrated that 'flick' down breaker that montolit use and it DOES make a difference, trust me on that!!
i use a ts40 plus for ceramics, but i like the tx700 because i use it the most and you can break with more variation imo. i like the clearer view of the line too but my next cutter is going to be a sigma max 1250mm... or even the 1500mm one. i will be buying it for all the reasons above.
i will by pass the 900mm version because i might as well be efficient with the money in this climate and buy one cutter that covers all scenarios back down to the tx700...
i know we have some banter on here but like in all trades, you have to be open minded and use what works for you.
this year, i will buy a sigma max and i will keep my ears and eyes open for a montolit mini piuma or master piuma upto 43cm for mosaics and for quarries etc. we are no different to joiners in the fact that we need quite a few cutters and some cutters tick the box more for certain aspects of tiling than others, so go with what your head tells you because normally that the right decision...
best of luck and go with what you ffels right because you'll be using it ;0)
ed