Well, remember that the 'learning curve' is that of the software, and not the user.  ;-) Having a clear, articulate and non-regional-accented voice helps, of course, but even after training, voice dictation software is subject to many of the frustrations of OCR. In particular, I've always found it difficult to shift between voice and keyboard to correct errors, and have never mastered voice commands to do cleanup.  With that said, though, voice dictation software has continued to evolve, and is remarkably efficient given the all-too-human variations in the way we speak. Be sure to get top-quality hardware (microphone and sound card, and/or dictation recorder) to go with the software, though, or you will have even more frustration.  The best use of VDS that I've seen has been to generate a 'rough draft' for your secretary or legal assistant to 'clean up'. Most VDS (and Dragon is typically among the best of the breed) will allow the person cleaning up the draft to actually hear the voice dictation, to assist in correcting the text.

Regarding Voice Recognition: I am surprised that this technology has not gotten more penetration in the legal profession.  I am strictly a two-finger pecker, but I have been using Dragon 8 Preferred for the past year and truly love it.  I believe that I am now as efficient as the most accomplished typists; it is the product that most vivifies for me the opportunity of technology.  All of the literature acknowledged that Dragon is the highest-performing product out there.  I would say I run about 99% accuracy, well within the accepted error rate for e-mails, and the more you work with it, the better it gets.  Every word it types is always spelled correctly; the trick is to make sure it typed the correct word.  Counter-intuitively, it is far more accurate as you speak faster (within reason) and in longer phrases.  I can see a slight drop in accuracy when I am on the road in a new environment. I have trained it with more than a thousand terms of art within my niche or the legal profession -- definitely worth the time to train it correctly each time a word is not in the vocabulary database.  I use it for 100% of my e-mails and for the shells of letters or "rough drafts" that Steve Tyler mentioned.  If you like, I will send you a copy of my list of key commands that I digested from the owner's manual and keep under the glass on my desktop.  And if you are ever in Annapolis, stop by and I will give you a demonstration.

I also use Dragon 8 Pro. Pricey but and excellent tool after a period of use.  Memorizing the verbal commands and a good quality microphone will improve your results.  But, I have phat fingers and the coordination of Gerald Ford, so it greatly improves my efficiency.  An alternate, is Cyber Secretaries at www.youdictate.com.  If you do less than an hour of dictation a day, or more is the most cost effective option.  You will spend less then 20/week.  Free to setup and they bill your credit card.

http://reviews.cnet.com/Dragon_NaturallySpeaking_Professional_8/4505-3528_7-31228939.html?tag=cnetfd.wk