If you look at the situation I don't really blame HBO for that. HBO sells content to the cable companies, and the cable companies have to deal with the end users. So HBO might get a little less money than they could if they avoided the middleman, but on the other hand, they don't need to deal with sensitive customer data and huge customer support call centers.
I occasionally watch things with my friend who has access to HBO Go in our office. It's horrible. Adaptive bitrate streaming is slow to switch or nonexistent, buffer times are too long, aspect ratios are often handled incorrectly in their player, and even figuring out how to log into the damned thing is an absolute nightmare. The Netflix user experience is vastly superior.
This is basically my answer to ndvivedi. In addition, I would add that I've had better quality from the Xfinity player, which also lets me view HBO content.
I've found HBO Go quality to be a bit too poor, even on a great connection.
Neither are nearly as good as Netflix, which I can force the bitrate using CTRL-ALT-SHIFT-S, let it buffer for a little while, then watch it straight through without issue. (Granted the secret hotkey is a little unfair, and HBO Go may very well have one too. That's the least important part, though)