I've made two log cabin quilts in my life. My only regret is that the first one I wanted totally scrappy, and I drove myself nuts cutting lots of different strips in all the necessary sizes and then trying not to duplicate any fabrics in the block. The second time around, I used the same fabric for all the logs in the light color, which made the whole thing much, much easier.
The first time, I cut all the logs in advance. I don't always have perfect seams, so some of my blocks weren't perfect, but oddly enough all the blocks fit together fine. The second time, since I was using the one light fabric, I sewed blocks to strips of the light fabric and just cut up the darks. It went much faster, and I was able to trim as I went and things stayed a little straighter.
I think either way is fine, it depends on how you feel about detailed work. I like quick finishes!