I agree partly with Rod, but Steve has a very good point as well.
Additionally, there's no mention of the corresponding websites of S&T and Astronomy. I think they are already using the internet more to their advantage. Especially Astronomy, as they have a well-thought out site with lots of information and easily navigatable. The S&T site is not as good, however (I guess the editor doesn't know that a serif font is not very good for onlilne reading...)
A good website is much better than an accompanying CD, like the sky at night has. Their website is almost empty with only basic stuff and a very quiet forum.
Personally I hope those ebook readers will become popular soon. I don't mind reading electronic books, but the current computers and their layout just doesn't offer a good way to read. eBook readers are just electronic books. If that would get mainstream, S&T and Astronomy and others may just as well distribute electronically.
In the meantime, I just renewed my subscription to Astronomy for another 3 years.. here's to the future