The difference between the two products (beyond cut length) is minimal, the PTC640 model additionally has two retractable lateral legs (to hold in place the large tiles) and an abutment on the central slider which cuts deffectuer in series.
This tile cutter (PTC640) is impressive because of its size (XXL), massive and clever, he makes 99cm long, 30cm wide and 29cm in height and weighs approximately 9kg (PTC 470 only 7kg). The materials used are very good, cast aluminum, nylon spring-loaded trays (easier to cut), precise rules'm booked on the strips lock (metal screw with a molded nylon head), a favorite jaurai my system completely identical metal (screw + head).
Bosch has pierced the base to create two carrying handles, it's really convenient given the size and weight of the machine.
In use, it is a formidable and well thought product, the cuts are precise and allow the lever arm gently cut the tile, the central guide is equipped with a handle to locked and unlocked BE easily, it is very simple with this system pose a heavy and cumbersome tile, weight and non-slip pads Lengin facilitates stability.
I cut different types of tiles (wall and floor) with a model making 12mm of thickness, the result is final => maximum efficiency, precision cut! The cutting blade is easily removable with the help of a screwdriver, I do not know the price of this accessory currently.
To: quality, finishing, cutting precision, carrying handles, the balance of the tool and its ergonomic design, the benchmark for cutting at 45 °.
Against: nylon screw head, not for every budget ...
Conclusion: Forget the lack of stability cuts tile good walk, imprecise cuts that go with it, this is the antipode, he really needed, Bosch engineers are really doing a good job, its weight gives it great stability , details are designed to simplify operations, cut a pane has never been so simple and effective, a very good tool simply formidable.
Pdf guide at: bosch-do-it.de/media/media/garden/gardenmedia/manuals/857254_1_609_92A_0HA_1405pdf..pdf