The creator of #Misskey:
“It's sad that when Misskey federates with other software such as Mastodon on ActivityPub, I only get complaints due to different behaviors (which of course comply with AP). (There are only criticisms, but I don't recall any appreciation at all.)
Also, for some reason, when there is such a difference in behavior, it is often assumed that Mastodon is correct and Misskey is incorrect/has its own opinion (in fact, the opposite is often the case).”