It doesn't compare to the streams of similar stuff on Netflix or Amazon.
Does the quality improve for paid subscribers? I was getting 3 dots on my Roku. Is that the best stream available?
I'm unsure what 3 dots indicates but I also saw 3 dots. I tested the same show (Doc Martin) on Netflix and AcornTV and these are the average bit speeds I saw on my router.
Netflix (Better video setting) 1300 kbits/second
Netflix (Best video setting) 2000 kbits/second
I'm unsure how to quantify this, but the Acorn feed seemed to be equal too or better than SD. None of the streams were in HD, but all three streams looked decent to me.