I guess I find it hard to understand how portability outweighs functionality. Especially when the solution is a poor compromise. Currently, the combination of my iPhone and iPad seems to cover my needs adequately.
Your requirement needs also play a role in what will work for you. If you are looking for a E-book reader then the size is important. But you are over buying if you get a iPad or Samsung Tab for just that. For myself I do not use the iPad for book reading, I use my iPhone. It's small but the key is I always have it. The short times that I'm waiting around I just pull it out and start reading. I've read more books in the past year than I have in ten years.
If your adding web surfing to that then I must disagree on whether a Samsung Tab adequately fills that need. I've spend a lot of time with the Samsung Tab and I do not consider it pleasurable to use. I place it about 30% better than the iPhone. Which would probably mean tha in a pinch I would use the iPhone since it is always handy. Then problem with the Tab is it stills doesn't fit in any of my pockets so it's still a carry situation which means I have it only when I decide to carry it.
I have begun to use the iPad for business meetings where I use Soundnote to record the meeting. The nice thing about this app is you can take notes and it knows where in the recording you took that specific note. I later review the notes and recording and place it in Evernotes which syncs with my PC, iPad and iPhone. I can later on review any of my notes on the iPhone when I get those short times when I'm waiting for something. In this application I don't see the Tab as being a solution. It's too small to do even short note taking.
I'm not saying the current iPad is perfect but I can see that Apple must of done a lot of user studies to get to the current form factor you see.