I use one and started off very slowly (1.5 MPH) but am up to about 2.2 now and yes, I do write on it. I had worried that I wouldn't be able to do it (I'm extremely uncoordinated) but it's no problem now. If I'm trying to work out a particularly complex scene or math problem, I will stop it for a few minutes so I can really concentrate, but I have found for the most part that it goes very well. My butt gets so sore after sitting for even medium stretches now that I have to get on it a few times a day just to stretch things out.
I have no tips for setup - my husband did mine for me. Though I do use a proper mouse and wrist rest as I do with my regular computer - much more comfortable for me than using just the laptop pad.
I have no tips for setup - my husband did mine for me. Though I do use a proper mouse and wrist rest as I do with my regular computer - much more comfortable for me than using just the laptop pad.