One thing that’s fishy about Proton is, the way how they’re turning away from the Fediverse when it comes to social media presence. It’s one thing when a company hasn’t discovered Mastodon yet. But Proton did have a Mastodon account, and they decided to abandon it. Not standing with the most prominent human-friendly (and in my opinion, most decent of all) platform and siding with the traditional, proven to be exploitative corporate platforms is something I cannot stomach.
The other thing is, I’m looking at my possibilities to replace Android with /e/OS in my degoogling efforts. And Tuta does publish their apps on F-Droid, which is a major advantage.
Here are a bunch of arguments pro and contra: https://m.youtube.com/watch?v=nvdcDuIZVvg