Signal, Telegram, and Whatsapp all have very feature rich desktop apps. I personally love Whatsapp and the fact that I can go to a webpage, scan a QR code on my phone and have a functioning desktop experience regardless of where I am. iMessage doesn't "just work" if there's degraded functionality for people outside the Apple ecosystem. I'm not sure what good enough means, that's really specific to the features you need. I actually strongly dislike how terrible sharing files between an iOS and Android user is if you choose to stick with iMessage. What's worse is the poor file system structure that iOS exposes where you can't manipulate and share files directly. If I want to share a song I have saved on my phone through a message, I should be able to share it like I would a picture. Having iMessage and sending to another iMessage user doesn't help in that situation. I'm also not sure what country you live in where you imagine everyone has a single messaging platform. Most people I know just use multiple apps and are willing to put in the effort it takes to switch apps.

Signal's desktop app takes, and this is not an exaggeration, minutes to start on a desktop once you have a few thousand messages for it to chew on. Signal also likes losing your login besides so you have to re-pair it to your phone, losing message history on the desktop in the process.

Messages is instant and doesn't lose history. And nobody I know uses Telegram or WhatsApp. If they work for you, then more power to you, but they do for me. Because with them I can talk to anybody if I need to, and if Android people don't like getting 3GPP videos or whatever that's just not really a problem that I care about.

The bar is really, really low. I'm sure WhatsApp or Telegram pass it if you know people who care about them. I don't, and I suspect most Americans are in the same boat on that one.

I care about how media gets transcoded. Effective communication is based on clear communication.

Signal on desktop with more than 10k messages opens in less than 10 seconds for me. Similarly with Whatsapp web. The only time Signal desktop has "lost" my login is when I uninstalled and reinstalled it on my phone. Which makes sense because it means it refreshed the cryptographic keys associated with my account.

Signal doesn't have an easy way to transfer messages to desktop or messages to a new phone by choice due to privacy reasons. It's not a decision I agree with, but it's a decision I understand.

Whatsapp is fine in terms of transferring messages and is instant. It's better than iMessage because it has the same major features while being platform independent. The unfortunate thing actually is that iOS makes it harder to backup the actual database of messages for something like Whatsapp or iMessage because it intentionally hides the files from you. I know many friends that have gotten upset that they lost their messages, because their iPhone died for whatever reason. It's really hard to recover data from a dead phone without paying a lot of money, if it's even possible. On the other hand I use a microsd card in my Android and my Whatsapp database is mirrored to it. I have some messages going back more than 10 years without having to use any sort of cloud backup solution or rely on the good grace of itunes backing things up properly. You need root access to get the Whatsapp key on an Android, but once you have it, you can decrypt the copied message database on desktop.

As of Oct 2021, there's an option to make an E2E encrypted Whatsapp backup based on a key of your own choosing. That means I can use a cloud backup and still maintain privacy over my data.

I care about making it easy for others to be able to communicate with me regardless of what they use, you don't have to care though.