Eshell because it is consistent cross platform and I switch often for work/etc. Sometimes I’ll use bash when I really want a native shell.
I used fish before eshell and I really like it, the auto complete is nice, but eshell has autocomplete and since aliases and other configurations are in my emacs config, they sync cross platform too.
It’s not worth it imo unless you’re doing a bundle with other Apple services (coming from someone who did switch).
If you do decide to switch, there’s software that will transfer your playlists over but if you use folders in Spotify they are not there in Apple Music which can be annoying when you have a ton of playlists.