I also left engineering for law. Money was a factor when I applied, but also I did not like being pigeon holed in my engineering career. I do patent litigation, so I get to see discovery on the whole system as opposed to portions of it for a variety of technologies (i.e., network security, semiconductors, mechanical devices). I only had about 2 years of engineering experience (working in defense industry), but found the career boring and the pay low (~60k starting vs $160k starting in big law (which is now $205k starting)). Granted, I do think if I went to silicon valley when I graduated, I may have found a better position at a start-up environment. After 10 years of patent litigation, I do find it boring, but at least I am paid well comparatively to my SV engineering friends.