It’s a complex topic, there have been lengthy discussions and will continue to be.
… and the only definitive answer is that there is no single definitive answer.
Kai uses a Mac, I use a Raspi, other power users I know of run Windows NUCs and yet others docker and ESXi VMs.
Because if one of us does rank all options using the categories quoted above, each and everyone of us comes to a different conclusion. We all bring different experiences, knowledge and history to the game.
So the first and most important advice is: let any user decide for himself.
That’s why I proposed the introductory paragraph to look the way I did and it does now.
But we still need to give a recommendation to the undecided.
For these I believe a Raspi 3 is a prime candidate, for two specific reasons:
a) it’s cheap
In buying and in terms of energy cost in 24x7 operations. Note you can and should have multiple units long term - at least one as a backup and eventually another one for testing.
b) only for Pis there’s openHABian to relieve a newbie from the difficulties of properly setting up the OS
Or tell me (a Linux guy).
@Celaeno1 your diagram does not apply to the mostly tech-affine group of home automation users.
And you’ve just been killed twice (read: your statement chased away 100% of two potential new OH users)