Would you recommend this audiobook to a friend? If so, why?
I have been trying to chip away at Finnish for years, and have learned enough of yleiskieli (the standard language) to recognize from the first 4 units that this is the real deal. It won't make you as conversant as a puhukieli background will, but at the rate modern Finnish in the different dialect regions evolves, there is really no way to gain that background from a course; for THAT, you'd have to go to Finland and start chatting people up. For the standard language that will get you by, this is a fantastic and solid beginning.
What other book might you compare Finnish Phase 1, Units 1-30 to and why?
There is really no comparison, since there isn't yet a Rosetta. However, The FinnishPod or Livemocha thing would be close correlatives. This is better and less pell mell. However, once you GOT the background in this, those other resources would be a great way to try to add to your vocab and your ease with case endings. Do NOT try to learn the cases the way you would in latin (by studying them ahead of time). That would ignore the organic way Finns use the cases on a daily basis.
Was this a book you wanted to listen to all in one sitting?
Take their advice and go unit by unit, and don't advance until you get 80+ percent accuracy on your current unit. Do a unit a day and you'll be surprised how much sticks.
Any additional comments?
Finnish is a language that people say is terribly difficult. But that's only because inflected languages are so different from English. This method demystifies that by giving you the forms gently. Like any language, it takes time and love.