I chose the Insight Guides phrase book over others because it comes with a free app. Supposedly.
The app is not available on Google Play. Tried downloading it via the Insight Guides website and I just get a 'something went wrong' message. I messaged Insight Guides to try and find out if it was a temporary glitch and 2 weeks later have received no response. I feel conned.
It still gets 2 stars because it's a reasonable phrase book, but I wouldn't have bought it if I'd realised there was no app and no customer service.