Personally I find that Tilemaster Adhesives Lightweight saves tiling time. The grip on walls is outstanding, press and twist and forget it - even with 600x300 tiles, It makes tiling the top of window recesses much quicker, and you can tile straight down from a bath edge to the floor with hardly any messing about. I discussed this with my tile supplier who tells me that it uses a new technology using glass particles - apparently no other adhesive manufacturer has this technology at the moment. Mark from Tilemaster might be able to advise if my information is correct. So quite apart from better coverage per bag, it measurably saves you time when fixing a whole bathroom.