My N810 was abandoned by most long ago, and it's still an entirely functional device. It still does exactly what I bought it to do, and it still travels with me everywhere. Barring an actual need for a physical repair, I suspect the edge will hold up just fine.

In terms of other devices, I'm still keeping my eye on the ASUS Eee Note (800?). It's a bit more basic than the edge and uses non-backlit LED instead of e-ink, but it's due out in the US this month, rumoured to be under $200 and handles pdfs well. If I wanted a full-blown tablet PC, I'd go that route, but I'm not in the market for an entirely new laptop (at laptop prices) and would rather live with the limitations of a dedicated device than use Windows again. (Not bashing, just a statement.)