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)
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)