Well, I am digging through the forum day after day
Concerning the Archos, mine is generation 4. It is not tweakable. It reads PDF files, but it is quite slow, and in fact unusable if you want to read more than 5 pages IMHO.
Concerning reading on the eeePC, one problem is that it is an illuminated device. I already face a LCD screen about 8 to 10 hours a day (working as a SEO consultant). At the end of the day my eyes are sometimes tired, especially when i read a lot (even if I reduce luminosity). So e-ink may be a solution. An other problem is that the eeePC screen (1st generation) is not very clear and is of a low resolution (800*480 - 7inches ). Last is that the machine is sometimes slow when dealing with large PDFs (Using FBreader on Linux Mandriva).