When first running the app, you are asked to choose your provider; once done you log on with your HBO.com registered email and password.
I found a little glitch with the iPad version. When I got to the point of inputting my email and HBO site password, I was told that my email address was already in use. I did have HBO GO registered on my Mac, but it wasn't running at the time. After some head scratching, I entered a lesser-used email account along with a different password and it was immediately accepted. I don't know if this is widespread but it did happen to me. Oddly enough I didn't have this problem logging on with the iPhone version which took the same authentication information that was stored on my Mac.
According to the documentation, you are limited to having only one device use the service at a time. This oddity in the system lets me use the service on my iPad at the same time as either my computer or iPhone, but didn't let me to access the service using my iPhone at the same time as my Mac since it had the same authentication.
When logged in, you'll see a moving screen of suggested programming which changes direction and speed depending upon how how you tilt your iPad. There are category buttons for "Movies", "Series", "Comedies", "Sports", "Documentaries" and "Late Night" along the bottom of the screen. As shipped, you can't access "Late Night" programming unless you activate parental controls by creating a PIN code. After that's done you're set to go.
Choose a category, like "Series," and a scrolling screen of all the available series displays. A nice addition is that old series (all the seasons of The Sopranos, Deadwood and The Wire among others) are all there. This is not something that you'll get with HBO On Demand which is available from a host of providers.
Choose from "All Series", "Featured Episodes" or "Family Series" to narrow down your selection. Tap on a show in a "Series" and a left or right scrolling list of every episode is displayed.
When you tap on an episode, a short description is displayed along with the option to "Play." If choosing a show that is a "Series" or a "Special" you can tap on "Preview", which will play a trailer. You can also get "More Info", or add the program to your "Watchlist".
If you choose "More Info", you'll see a scrollable display showing a description and listing of all the cast and crew. You can also play the program from the upper left hand box while in this mode. The video will play in the window while all the other information is displayed. To make it more convenient, a tap displays the program in full screen. This option can be toggled back and forth.
"Movies" are displayed in a number of ways. In landscape mode you can choose A-Z which brings up scrolling alphabetical listings of dozens of films. Choosing "Collections" brings up a smaller listing and tapping on one choice displays the movies in that collection with picture icons for each.
It's also possible to choose "Genres" activating a drop down menu listing types of movies. This leads to another screen with movies sorted the way you prefer.
In portrait mode, a printed listing of items is shown. Choose one and you'll see a screen giving you information on the show and letting you once again choose to "Play", "Preview", get "More Info" or Add to the "Watchlist". You can view the show in either portrait mode which makes it too small, or landscape mode which affords you the largest possible picture.
The video quality of the program shown depends on the speed of your connection, and can range from pixilated to perfect. I was quite impressed with the quality I watched using a WiFi connection. With a speedy connection the picture is as good as if the video resided on your iPad. When watching something and tapping on the screen, the usual video controls are displayed along with one for Airplay, but don't get too excited about that. HBO GO will stream audio but not video, at least not yet.
On an iPhone the controls are much simpler and harder to navigate. The types of shows are displayed in text, but with more taps than needed on the iPad you can get to everything. When you make a choice, you do get a graphic display but only in one column causing a lot more scrolling.
This is one incredible app for HBO subscribers on supported services. It works exactly as you think it should. The depth of programming is vast, and under the right conditions the picture is perfect. I wouldn't be too surprised if HBO eventually offers this as a separate subscription product eliminating the providers altogether. At least I'm sure that HBO would like to, but I have a feeling that the providers would have some other thoughts on that.
If you are currently buying HBO from a supported service, go and get this app right now. The possibilities are seemingly endless. Since it supports 3G you can use it in the car (back seat only please), take it on vacation, or anywhere (which probably means just in the US) away from home. If this is the first version, and they got it so right on the first try, I can't wait to see what future revisions will bring. HBO GO deserves a place on my home screen and I can't say that for more than a handful of apps. I'm impressed.