PB is irrelevant
I haven't had PB since last summer when Comcast updated me to 50/10 and really I haven't missed it. PB was useful back in the days of 6 or even 12 Mbps connections, but as speeds increased it lost it's usefulness.
These days, when I can download a 1 GB file in under 3 minutes, the extra few seconds PB would shave off the download is meaningless.
Not to mention that I rarely find servers capable of actually delivering 50 Mbps download speeds, so PB won't really help in that case anyway.
Upload PB is still kind of useful, but the vast majority of people don't do a lot of uploading or if they do, it can be done in the background where upload time isn't as relevant.
The Comcast Disney Avatar has been retired.
Powerboost may be irrelevant, but they still need to offer faster upload speeds.
Those who are content creators, like me (and others), who upload multiple 30-minute videos to YouTube, would appreciate the higher upload - therefore leading to less wait for all the videos to go up.
This would really help me, since even though I have a dedicated uploading computer, because I still have to wait 8 hours for the first of 5-6 videos to be up and I have to do this at night.
Most ISPs offer *only* 1Mbps upload speed, or 3Mbps or 5Mbps. At my location, no one offers higher than 1Mbps, unless you buy ultra-expensive fiber Internet (which is not offered for my house, only for my business location).
[Of course, I can't upload on my business location, because this is not on company time, because I create content for others' entertainment, fun, and myself.]