I use my N810, but it's got some serious limitations. The 4.1" screen can be a bit of a pain with manga, especially when it's scanned with pages side by side. The transflective display isn't as nice as e-ink for reading. My reading speed is probably cut by 20 - 40% due to the small screen size. It won't read DRM protected ebooks.
Despite the limitations, I use the hell out of it. It's pocketable, the battery life is solid, I can get online with a real browser via both wifi and my cell phone, and it can double as a PMP. The e-ink devices are great, but their size and limited functionality outweigh the benefits.
As far as commercial ebooks are concerned, I don't mind losing out on them with the nokia. Until Ebooks are offered as a cheap($1-2) companion to purchased hard copy books, I won't be buying any of them. Most of the cost of a book is in printing, binding, shipping, and shelf space. To charge the same for a license to read the book indefinitely as they do for the paper product is a fucking travesty.