> The above discusses the marketed features

The above discusses what I notice in practical terms.

As a privacy nut, I want to use an encrypted messenger for my friends and family so I dove into the privacy aspect pretty deep. I work in security so I also understand the technical details. I also use Wire, Signal, Telegram, and Matrix/Element on a daily basis (and Threema ~weekly) so I know which practical pros and cons I run into for each of them.

> what I understand from people with actual IT security expertise

That would be me. Wire is solid. It's based on the same protocol as Signal and my employer (shortly before I started working there) audited the implementations and applications so I know the people that did this audit, and was later involved in a small architecture review as well. The reports are also open and available on the website of my employer as well as Wire's.

Signal goes one step further and does innovative stuff like sealed sender and private contact discovery, but this does not impact the security of your messages or calls. It has more to do with privacy, aka how much Signal is able to do with your metadata. All of the measures they implemented can be broken if they wanted to (SGX vulns, traffic analysis, ...), so I am hesitant to consider it a solid advantage, but it's now harder to get your metadata so it's still worth something.

On the other hand, there are the advantages (and disadvantages) I mentioned above. It's a trade-off and there's something to be said for each.

(Of course I speak for myself and my employer may have a different opinion yada yada)

> [Signal is] really the only option if you want real security

That's not really true as a strong blanket statement.

For message/call integrity and confidentiality: Wire and Signal are basically the same, because they use the same base protocol.

If you (also) mean privacy, then... it depends:

- Threema operates (app and infra) in a country with better privacy laws, and Cure53 audited them recently so their protocol should also be good. I'd go with them if I wanted the best privacy on a centralized service, though you don't get some of the fancier protocol features like plausible deniability (not that that's worth much, but it's nicer to have than not to have)

- Signal does innovative stuff but requires a phone number (in my country that's linked to a government-issued identity)

- Wire has infrastructure in the USA (big downside imo, I don't understand this choice) but their legal entity is iirc in Germany (which I would consider a similar jurisdiction as Threema's (Switzerland)) so that's still better than Signal in terms of coercion to hand over anything

- Keybase has none of these advantages but still many people choose it for their integrations

- Matrix-the-service I don't remember, but with federation it's fairly trivial to use your own home server so you're fully in control. This is obviously the best option, even if you'd not use e2ee and just encrypt-to-your-server because it's your server which can be in your house.

Pick your poison on that front, or go decentralized.

The aspect I cannot really speak to is exploitability, like how hard it would be to find an exploit that works on one of these apps. Best would be to have one that just shows plain text messages and doesn't do image parsing, video displaying, link resolving, peer to peer calling, etc. That is exactly none of the above and I assume that all of the above rely on system libraries for media/emoji/etc. parsing, so it should be about equal, but I don't know that for a fact.