I'm a user of the previous incarnation of this product called iListen. The Philips engine used buy iListen is substantially different from the "Dragon" engine of Dictate. While iListen was capable of adapting itself via "normal training" and also via "vocabulary specific training" Dictate does not have this flexibility.

Living in Australia were about 30% of the population speak english with a NON-NATIVE accent, I've tried with a few people, and the results are not quite impressive.

Also if you have a lot of foreign names of people and towns, Dictate fails miserably.

IF you are a NON-NATIVE speaker iListen is still a better option, and with this engine I don't really know if will ever be a product for "the rest of us"