I recently picked up a digital voice recorder. While you have to transcribe what your record, I find that I can record information a lot faster than if I was writing it down. I normally try to take note of the following: lens, aperature, exposure, filter, development, important zone placement, any other interesting details.
And so on. Works fairly well. But, as with all things, unless you use it, it won't work. Use a pen and paper, it'll work just as well - as long as you use it.