In varying degrees these programs all have their own unique abilities and ideosyncraticies. Just as every user has their own personal abilities and preferences.
Unlike text -to- speech the ultimate "objective" of command -and- control is to:
Some voice dictation programs, as well as many command -and- control utilities, come with pre-set vocabularies and dictationaries. These may [or may not] have an "open" vocabulary to customize with your input. You may have to "train" your voice and pronunciation to match your computer's expectations. With an open vocabulary you can train your computer to your voice specifications. Newer, and full featured, voice command, control and dictation programs self train automatically in the background as you use the computer. Some self training applications are so successful that only one user may use the program.
All Voice Pad Dictation and Word Processor programs are not equal. Some will be limited by "cut -and- paste", "drag -and- drop", or "clipboard" transfers to other files, applications, or programs. If the objective is to reduce manual file manipulation, there are less file transfers when voice dictation takes place inside the word processor or program application.
When selecting voice dictation software remember that these are "power - hungry" applications. Select a program that has power requirements [just below] your current system's abilities. These programs will run better and faster when there is power to spare. When there is not enough power these programs work poorly [with decreased speed and increased errors] while some may not run at all.
GOOD HUNTING AND ENJOY!