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I personally use the latest version of Dragon Naturally Speaking (ver 11) and really like it, though I'm not in a noisy environment. This new version was truly an upgrade to any previous version.
The initial tuning is not enough to be very precise, however, there is a very good built-in accuracy tool that you could spend 30+ minutes fine-tuning speech recognition. The accuracy tool allows you to select from a number of different speech types, i.e. easy reading, technical writing, etc. Additionally, it has an easy method to add words to the database when dictating, which really comes in handy.
Resource: Voice Recognition Software Reviews
Some of it depends on the person. All voice recognition software works better the more clearly people e-nun-see-ate (enunciate). Even so, I've used Dragon over the years, and it has gotten very good. The others I am not really familiar with. It is pretty close to the point of matching a good secretary transcribing dictation, and has surpassed mediocre ones. Really the only thing that you have to adjust to is remembering to verbally say punctuation (comma, period, etc.), but you have to do that with a lot of secretaries as well. If your office is loud, the accuracy will go down slightly, but not as much as you might expect. With a law office, that probably wouldn't be an issue for an attorney. I find that Dragon is perfectly usable for most dictation needs, but don't expect 100% accuracy.