Yea, Mars Volta albums take some time to appreciate.
I can say, though, that the first 4 albums usually had enough raw energy and power on the outside to bring me back every time, so I always got excited about it. Then over time, the beauty and genius of the music would reveal itself.
Since Octehedron, there is no skin-deep energy and the newer albums need more time to appreciate; the band is not barraging you with riffs and soaring vocals. And now with the electronic element, I have had to accept this new direction the band is going in. Had I not heard Octehedron before Noctouriquet, I may have been disappointed when the new album came out.