So when you're looking at a new encrypted data service with their own DIY implementation of cryptographic protocols, this right here is the most important question:

https://delta.chat/en/help#security-audits

This is good. It has been almost two years since the last audit, which probably encompasses a lot of software changes. But having any audits, and discussing that up-front in the FAQ and including documentation is awesome. It's good to have alternatives available.

Not anonymous like Signal and SimpleX. Doesn't have PFS.

Looks great to me... I've been using it for a couple a months with a friend. Working perfectly fine (besides a slight notification problem - probably coming from my android phone parameters but could not identity what)

We try to use it as a WhatsApp (and other big tech apps) avoiding when talking about sensitive matters.

I wish more people were using it!

If anybody has caveat, let me know....

Being email based means it's also asynchronous. Even if your comms have to move on flash drives in the mail, you're still good