14/Nov/2022
(* "only one" means "only one I've tried"; all based on first impressions; element/fluffychat are web/desktop versions; based on current release versions, not nightly builds or planned stuff)
custom stickers and emojis
cinnny was the only one that would let me set and use custom emojis and stickers
fluffychat would let me set and pick emojis, but not set stickers
neochat lets me pick emojis and treats stickers as emojis (also whatever way it handles them seems to be incompatible with nheko)
nheko would let me set emojis and stickers but only let me use stickers
element doesn't let me set/use stickers* or emojis. it has a button to use stickers, but doesn't pick up the stickers set by other clients
security
neochat has no encyption/verification support
all others support being verified and issuing verification
voice and video
only element and nheko could do voice/video calls
apparently fluffychat can do voice, but I couldn't find the button to
spaces
element and cinny are the best ones at handling/displaying spaces, only show rooms you are in, but let you also see the other rooms in the space. and are the only ones that can create spaces
fluffychat separates by spaces but has a 'discover groups in this space' section you can't hide, and it doesn't even at least show all rooms in the space
nheko lets you separate by spaces, but shows all rooms of the space independently if you joined them or not
neochat has a 'spaces' section in the room list, but it doesn't serve for separating rooms or seeing the roms in a space
room management
neochat doesn't let you change room permissions
neochat and fluffychat don't let you change user roles (I think)
you can't pin/see pinned messages in neochat or cinny