If you think wheeled cutters are only for use on glass tiles, please take a moment to reconsider. These were developed by Spanish manufacturer Rubi to help professional tradespeople installing large-scale hardened porcelain and stone tiles.  When such tiles need to be cut to fit precisely into unusual areas (awkward corners on floors and walls) the large mechanical cutters typically found on construction sites are too unwieldy for the job;  these nippers allow accurate shapes to be produced and are therefore also a wonderful tool for mosaicists.  I've just completed a not-very-scientific test, cutting Cinca porcelain tiles into quarters, the first five minutes with these nippers and then a further five minutes with standard nippers.  These nippers produced a significantly larger pile of accurately cut tiles and I am sure that they required less force from me.  They are expensive, but I think you will probably cut down on tile wastage.  The wheels can, as with other wheeled glass cutters, be loosened and turned when they begin to get blunt.  

Unfortunately Mosaic Workshop can't accept returns of cutting tools which turn out not to suit you, so please think carefully before buying.  If you are finding it very hard to make a decision please contact me as I may be able to lend you tools to try (you will pay a deposit, and for postage in both directions).  In the case of faulty goods we will, of course, accept returns - please see notes in the website footer.