I've been using Dragon v10 for a while - only for writing papers and reports because I don't find it practical for shorter things.
Yes, you need to speak clearly. But, boy, is it faster than my typing and lets me concentrate on the words rather than the keyboard.
And yes, it cost a few quid, but of all the software I've bought, this one is worth the money and I'd do it again. I can't say that for all the other bits and pieces that I've spent good money on over the years!