To those who have used both which do you prefer overall?
What has me on the fence with Sharkey is it seems overstuffed, and the vast majority of instances revolve around anime. I like anime, sure, but it's 90% of the content.
The extra features seem rad but it looks like you need to use the PWA to access most of them and there are very few misskey sns supported clients available.
Mastodon and Misskey are both getting a little overstuffed. Neither are particularly nimble, with Masto moving to further "professionalise" itself and Misskey (forks included) having way too much stuff on offer in terms of features.
Regarding clients, Kaiteki seems to be the best Misskey client I've found on mobile. The native PWA was an absolute pain the last time I used Misskey. The anime issue with it probably stems from it's Japanese origin and most big instances seen as refuges for artists banned off Twitter.
I've personally switched to GoToSocial, which seems to fill all the Mastodon-shaped holes without gulping down resources.
I use Sharkkey sometimes just as an experiment. I agree with you, the extra features are rad and it is much more aesthetically pleasing. But it is "stuffed" with far too many navigation options, some of them even redundant. Also I absolutely loathe character limits on Mastodon.
The inability to follow hashtags is an instant dealbreaker.
What you see in your feed has absolutely nothing to do with the type of software and everything to do with who your instance chooses to federate with.
Also PWAs are great.