I don't find them good for consuming except for movies on a plane. Movies at home? The bigger the screen the better. I'd much rather watch movies on my 42 inch TV from my sofa than my tablets.
Reading? I'd much rather use my Kindle Paperwhite. It's better on the eyes and soooo much lighter.
Browsing the internet? I'm a curious person and I click lots of links. So for example I'll come to HN and ctrl click every title that sounds interesting. Tablets hate this workflow as they start removing tabs. Even when it does work invariably I'll run into a page that doesn't work on the tablet. Maybe it's a WebGL page. Maybe it's a Flash page. Maybe it's a page that requires interactivity but does not respond to touch events.
Finally I'll want to comment on something or post something I found to my facebook or G+. In those cases tablets suck balls. Editing text in a tablet is a exercise in frustration. Trying to move the cursor, format, copy and paste. It's not fun. Pasting a link in the Facebook app doesn't generate a editable preview like it does in a regular browser and many other shortcomings.
I could go on and on. Some of these limitations I put up with on my phone but then my phone fits in my pocket and is always with me. My tablets though, really, I find them pretty useless. There's sole purpose at this point is to once in a while check out some new app someone tells me about. Otherwise mine are unused.