I picked up HBO when I got the $5 for 6 months deal. We're using it almost exclusively to watch Westworld and try to catch up on GOT.
We have had a Netflix sub for a LONG time, and IMO HBO doesn't offer anything close to the contents Netflix does. I'm looking at my HBO channels right now - Garfield the Movie, Princess Diaries 2, Role Models (Paul Rudd), The Shaggy Dog, Semi Pro, War for the Planet of the Apes, She's Out of My League, Peter Pan, Napolean Dynamite, etc. And they repeat for a couple of weeks. I look at my Netflix playlist and there's a huge choice of older movies (with a wider range of dates made,) a ton of interesting documentaries, a good number of Netflix originals, a nice vault of older TV shows (including some going way back in time,) My wife and I laugh that every time we browse through all the Netflix content we end up adding a couple of shows to our playlist, which is already large enough we have a hard time keeping up with it. Also, more and more of their content has a download option.
HBO has a few originals (I dislike Bill Mahr, not because of politics but because I simply don't like him for reasons that would derail this thread) like Oliver, Westworld, and GOT that we enjoy. But certainly not enough to pay $15 a month. Even at our current price, I scan HBO in the guide for a couple of weeks to try to find something to record and I rarely find anything.
FWIW