I confess that for a while, I shrank away from buying unmounted stamps that were not precut - the process of cutting with my KAI scissors was so laborious. I also love it when the rubber around the image approximates the shape - when I am stamping, even though its not clear, i still get a good "gist" of where it is going. (All Unity Stamp Co stamps come precut and premounted this way), and the thought of cutting an open mounting sheet in all its sticky glory with my scissors - well, yucko. So, I went the Alene EZ Tack It Over and Over glue method for a long time, but that stopped the first time the glue pulled off in a single shot when I tried to remove it from my clear block. it failed to stick to the rubber - though the block was nice and gunky.
I fell in love with the Chichibouillie stamps at Stamping bella. but they were - precut unmounted rubber. And here came the hot knife to the rescue. I had read about this method, but never tried it - but those stamps were calling my name... OMG. Its simply a matter of tracing and its like butter. WOWZA!!! (and I've switched to the EZ Mount thin... it is just enough cushion but not so much that the little images start to rock)