they're not ergonomic. not for reading. not for writing.
that is why they (hopefully) will fail.
i have one right now to read/write stuff on. i can't lay it onto my legs on a chair to read nicely, like i could with a laptop. the angle is bad, i want to hold it to see directly onto it. but holding for more than some minutes is annoying. it weights (no matter if it's not much weight).
writing on it sucks, too. gladly, i have a windows option, where i have the option to use the pen input instead of the multitouch keyboard (which i will hate on the ipad). and while you type with your hands, you can nearly not see on the screen anymore anyways, filling it wiht your hands.
so when sitting, you want to write with one hand, hold it with the other. the keyboard doesn't fit your setup, then..
no, they really suck. i, too, have a convertible. next version will have slate mode, notebook mode, multitouch, pen input (capazitive) etc. it will allow me to use the best of normal laptop, tablet, pen, fingers etc. that will be awesome.
normal tablets, no thanks. they completely fail at ergonomics. MASSIVELY.
and when they do that, they should provide some good counterargument. phones do have that: you can take them always with you. doesn't matter then, that they're quite small, quite slow. the portability is a huge gain.
what PLUS do tablets actually have? what do i GAIN from having one? i still wait for the one simple answer showing me a reason i should get one.. (i know some specific cases where i most likely will get one.. in the car, and for home-automation. maybe for djing, too.. other than that, no idea.. for the ordinary user, no idea)