i have the martelli and the olfa....the martelli is heavier and thicker. Also, in their dvd's they say (actually even recommend) that the lines are accurate and you can use them when cutting....(don't know if the others aren't but it's been recommended to me to cut using the lines on the rulers and not use the lines on the mat).....is the martelli worth the $$$....? I don't know since i've just received it but it seems to be better quality and I expect it to last longer....I also have one of their rulers....I must say it's nicer than the rulers that slide around.....my cuts have been more dependable and straighter....but you can use their rulers and their mats separately from one another....I do prefer their rotary cutters.