I have tried lots of other apps but I keep coming back to iTrans NYC because it works underground when you may not have an Internet connection. The other apps have some nice bells and whistles but none work underground which is kind of crucial!
While disconnected, you do have to put in a street address rather than just a business name like you could do while connected, so its a little less convenient.
Compounding this, I also have found that my "recents" list doesnt reflect searches I just made, but if I remember the first digit or two of the address it will often auto fill for me.
Another thing to keep in mind is that iTrans does not offer walking directions alone, i.e. without a subway component. Youre better off just looking at the street map for that.
I have noticed that the subway map needs an update. For example, the Broadway Lafayette F train / Bleecker 6 train connector has been functional for a few years now, but iTrans still tells me I have to go above ground to make that transfer.
Other than these nitpicks, the interface is straightforward and works well. I use it daily!
BeckyMalaria about iTrans NYC Subway, v8.1.1