Great product, works a charm on all the screens I've tried. I've just used it on a MacBook Pro, TomTom, Nokia phone and Blackberry touchscreen. All have come up sparkling with practically no effort (and the Mac in particular was pretty grubby).
N Salter writes in another review here that the liquid is thick and is hard to remove without smudges. I suggest that perhaps they have used too much of the liquid. It says only use 2-3 drops even for a full laptop/iPad and it really means it. i used one drop on the old style Nokia (not a touchscreen) and it took a while as the screen is so small, but once I rubbed it all of it is now sparkling.
Seems like the sort of product to keep in a man-drawer and would last for 10 years (a bit like the original Brasso then :-)
Oh and the cloth seems big enough to me. Again, it really only takes a few drops of the liquid, if the cloth is sodden when you finish you have used too much. I did all those items above in one go and the cloth is barely damp.