I was on Timespan (until I couldn't afford it anymore). It made a great difference for me overnight, especially improving how I felt first thing in the morning. Between improved quality of sleep from not having to actually get up every few hours, to the slow release dose, I felt so much better in the morning when I was on it.

The only issues I had in the beginning (which I had with regular Mestinon too) is that it made me hungry, so with the Timespan for about the first two or three weeks I would wake up every night between 2 and 3 am and have to have a little snack. Just started keeping a cheese stick or a couple of graham crackers next to the bed.