Since you;ve never had one, you've clearly never taken to typing on it. I borrowed one for slightly longer than a week during an extended and in depth comparison on several e-readers. After just a few hours with it, i was typing on it at near my physical keyboard speed, and had no issues writing a several page article on it, not typing long forum posts or complex e-mails. I can hit about 80wpm on a full keyboard, about 65 on a laptop keyboard, and I was hitting about 55 on the iPad, with little practice. On netbook keyboards, i fall under 50wpm, so to me it was BETTER than an ultraportable's cramped layout. With time, and getting used to auto-complete (which i think should be ported to desktop OS as well), i could easily hit 60-65wpm if I tried.
Do i "like" typing on it? compared to a full keyboard, hell no. compared to a laptop keyboard, I dislike them both about equally. Did it get in the way of my productivity? barely enough to report, and over time that would change to a "no."
Why have an ebook reader that is JUST an ebook reader? I can not only read on an iPad, i can edit a word doc, respond to an e-mail on the commute to work, play a quick game, watch a video or podcast at lunch, watch a TV episode while the wife is watching some other boring show without having to leave the living room to do it and hear her bitch about how I'm not helping watch the kids, it's SO much more than an ebook reader. Heck, we slung it from the back of the drivers seat and played a few Disney movies for the kid on a road trip while I had it. The longer I had it, the more uses i found for it. I did an exhaustive demo of the Kindle, kindle 2, Nook, and iPad, and recently added the Tab to that cycle. the ONLY one I regretted giving back at the end of the week was the iPad. the only reason i don't have one yet is we're in the process of buying our house from it's owner, and cash flow is restricted.
I know people who use them to do business presentations, access CRM systems, review documents (which is SO much nicer on a Portrait display than a notebook, let alone a netbook or ultra-portable), deal with the flood of e-mail, and a dozen other things with them. I know a lot of people who simply shifted from having an ultra-portable plus a "real" notebook, plus a machine at home to simply having an iPad and one good laptop they rarely lug around. I know several who just abandoned the notebook al together and use only a desktop PC now with the iPad. the iPad can do 80% or more of what most people do in a day well, and most of the rest with little trouble.
A week with the Tab, btw, cramped virtual keyboard, no productivity apps suited to the larger screen (no good productivity app at all to compete with Pages or keynote), PenTile AMOLED screens suck for reading text, and the battery dies too quick. If it was 9-10", with twice the battery and Android 3.0 it might fly as a real competitor, but it was little more than a big android phone without a phone and certainly no help on the productivity front, and the poorest e-reader i reviewed.
As for e-readers, if all you're looking for is reading, and are looking to spend a very small amount of money, or you do most of that reading outdoors in bright light (where optometrists tell you NEVER to read due to heavy eye strain issues) i can recommend an e-ink based system (i preferred the nook to the kindle options, but only because it was a more open platform not locked solely to Amazon's book store). That said, if you read regularly in poor lighting (subway, dim lit rooms, in bed, etc), stay the hell away from e-ink. Although very sharp in normal light, and a bit less effected by bright light (though it was still effected), e-ink was the worst performer in sub-ideal lighting conditions, i even liked the AMOLED screen better in the dark. If you can spend a bit more, a used or refurn iPad is a better bet, especialyl if you don;t already have an ultraportable and are interested in doing anything at all more than reading.