iTravelGo is a US$0.99 app that is limited in cities, but very deep in the information it provides about them. The app has been released today in the App Store.
The 36 cities include US destinations Los Angeles, New York, Chicago and San Francisco, plus other popular places like Vienna, Madrid, Hong Kong, Rome, Beijing and many more. Information includes maps with driving directions, the best attractions, restaurants and hotels. Hotel rooms can be booked through Booking.com directly from the app.
I found the app quite complete. Almost all of the information you want is built into the app, except for map details, web links to hotels and other ancillary web-based information. That's a handy feature if you are out of the country and don't want to rack up data costs.
I liked the handy phrases and a brief history of the cities, and detailed transportation maps and cost estimates for taxis.
The app has many photos that can be useful in evaluating a restaurant or a hotel. Rough prices are given for all attractions, hotels and restaurants, and little details like WiFi features are most welcome.