They're slightly different interactions and I (not the commenter you replied to) use both. I feel like the bottom swipe is a discrete action that takes you straight to the last app, and I use it when I'm very confident, like a one ⌘-tab with no hesitation.
The half circle is more like starting to activate the app switcher, but confirming the next/previous app immediately. The difference is that it gives you slightly more time to see what you're doing and you can bail out into the app switcher if you change your mind in the instant the apps come up. That's actually the only way I ever open the app switcher; I feel like the swipe up and hold is way too slow.
The half circle is more like starting to activate the app switcher, but confirming the next/previous app immediately. The difference is that it gives you slightly more time to see what you're doing and you can bail out into the app switcher if you change your mind in the instant the apps come up. That's actually the only way I ever open the app switcher; I feel like the swipe up and hold is way too slow.