Probably not worth it, if you aren't really into it. The first one gave some semi-interesting background on the gameworld, but the second one was, IIRC, absolutely dire.
I think I read both of them in a plane, hmm... :D
I thought the first one was fairly decent. It was mostly about political intrigue and did a nice job of introducing the world.
The second book was fairly rubbish, but I find the wardens to be terribly boring. I doubt I'll read the third, I haven't even been able to get into DA2 so far.