Right at this moment: content and performance.
If I start looking around at Peertube, will I find anything I'm interested in watching? There's a LOT on Youtube right now, what's on Peertube?
There's a tendency for alternative platforms to be wretched hives of scum and villainy. LBRY for example felt like the place racist shitheads were banished to when banned from Youtube. The difference between LBRY and Peertube seems to be "something something blockchain."
I noticed a video from a channel called The Giddy Stitcher titled "How to start a (good) Flosstube channel" which for a second I took to mean Free Libre Open Source Software tuber, as if she was going to give tips on how to run an channel on Peertube. No, apparently "floss" = textile arts/string/whatever and that term is similar to "woodtube" for Paul Sellers et al. She apparently uses Peertube to mirror her Youtube videos, and gets thousands of views per video on Youtube and maybe a dozen views on Peertube.
Anyway, watching this video, it buffered HARD. It got better after awhile but...you remember how, back in the day, you could just pause a video and it would buffer? And how it kinda doesn't anymore? It was also that. They don't offer lower qualities below 720p50 which probably doesn't help; I've seen Youtube jump all the way down to 144p to keep the video playing at all.
I know, Peertube is "some people" while Youtube is run by Alphabet. But, maybe we should standardize on lower resolutions and aspire to HD later on, huh?