as an end-user Akkoma has felt better than Masto so far
as a sysadmin the fact that Akkoma has a single process does make me worries about scaling it if needed, but... it also means it was easier to setup and that it's easier to manage, backup, move around, etc... which makes it better
if you don't run a 100000000 user instance then srry but Akkoma kinda is just better anyway.