It has really changed my solving technique - the hand held device I have doesn't do pencil marks and that makes a big, big difference for instance and having to take into consideration the postion of the cursor also makes a difference, and, for some reason, the timer on this thing makes a difference (I can't turn it off).
I solved one on paper this morning and felt the usual sense of achievement but missed the wee tune of celebration

Even if Pappocom could come to an agreement with another company making these devices, I'd buy it.
Luna