I read a lot of documents on my laptop. On one with a good 14"+ high-resolution (1440x900 is a bare minimum; my prior non-wide 1400x1050 was better) screen, it works pretty well. Unfortunately, it's too big to use in coach.

1280x800 12"-13" is marginal; 1024x600 netbook is pretty bad.

One big iPad (or convertible-tablet) advantage is being able to read in portrait mode; if you have an application and content that can reflow text (ie NOT scanned PDF documents!) it can be really nice. For non-reflowable documents, especially scanned ones, the size and resolution is too low.

What I really want is a 14" non-widescreen convertible tablet; Gateway used to make one, but the prices were usurious.