I don't actually know - I have accounts on instances with both, but I don't use them regularly, so I don't have anything to compare

Foundkey (because i usually lose mine)

None of the above, they're all too busy and animated and would stress me out.

akkoma

akkoma gang, akkoma strong

Foundkey

So far, I like Calckey the best, but I haven't joined any Foundkey instances so I don't have much to compare with.

foundkey, because amiga tracker

Neither

Foundkey, but I do also have an account on a Calckey instance too.