If you're looking to use dictation extensively, the built-in Windows Speech Recognition application may be more suited to that purpose.
Running it alongside VoiceAttack is not generally recommended in case one interferes with the other, however if you keep that in mind if you encounter issues (so you can shut down one and check if the issue still occurs in the other), it's worth trying.
That said, the Microsoft speech recognition engine is best suited to predefined commands; For a speech recognition system that is more focused on dictation, you could consider Dragon by Nuance (other speech recognition applications may also be available; This package, previous know as "Dragon NaturallySpeaking" is possibly the most well-known, though).