Very helpful, with some flaws
The LRV and subway maps seem jumbled together, the app instructed me to get on the LRV and off the Metro without ever changing from one to the other.
Also, a little more detail on the walking maps would have been helpful. .
Despite these limitations, I found the app very useful in planning what to see and where to go. I would buy it again.
Rdfaleph about
Istanbul Travel Guide (with Offline Maps) - mTrip