I have a Surface Pro 3 and have had it for a little over a year now. I've been very happy with it -- it runs a complete version of windows, and so I can use all of the programs I need for my work. I've found it is fairly to use on a plane on my lap. I can usually get about 5 hours of battery life out of it -- 6 if I turn the screen way down.
I don't see why it wouldn't also be able to do the tablet things you've mentioned as well. I don't use it as an e-reader, mostly because I like the feel of actual paper and still buy actual books more than anything.