Mac, reading over time won't get cheaper
If you stay with your reader, it probably will. But as geeky as some of us are, chances are that you buy a new reader before the old one breaks or before it paid off.
Ok, the grey levels. Both of my Sonys seem to have 8 grey levels. I have lots of pictures and charts in my pdfs and I never had the feeling I was missing something. But that's just me. I concentrate more on the text and have the charts just for quick looks. Others may handle this differently.
B&M stores. Hmmm. The ones we have in Germany are not that great. I had the chance and lived in the US for 3 years and I preferred the stores there over the German ones. My Zune is a (1st. Gen. Microsoft) MP3-Player only. But compared to the Ipod, it was the underdog.
The Eco-reader is sold as the BeBook here in Germany. But I haven't actually seen one yet.