Group SMS and MMS messages weren't supported by the backing service. As group messages became more popular as more of my friends got smartphones, I'd miss more and more communications that my friends were having. Additionally, there were times when even regular SMS messages would be delivered minutes or hours late. The whole system felt unreliable. It felt like the only purpose was to send outbound messages from the computer.
At the time that I switched, the Hangouts app was having some difficulties of its own. The biggest issue I had with it is that Hangouts would try to upgrade me from an SMS chat to a Hangouts chat with someone, when the recipient was an infrequent or Gmail-only Hangouts user. Google would recognize their number and send Hangouts messages, they wouldn't see the messages on their iOS device because they didn't have a Hangouts app, so to them it would seem like I had stopped responding.
Same gripe I've had on iOS past, could never figure out if my response was going to go over sms, imessage, or email, and if email which account, so I just avoid as much as possible, and don't setup additional accounts on my iOS devices or ones i set up. Mostly to avoid getting "why am i getting email responses to my text messages" questions etc.
Not saying it's hard or complicated, just hard and complicated enough for me to avoid. When I send someone a message there should be no guesswork involved. Not sure how both google and apple could mess this stuff up so badly in their attempts to make it "just work." Or how much of the issue is the "use only our ecosystem or your shit may to break" mentality.
Apple doesn't care if you can communicate with non Apple users. They have their iMessage population hostage. Those people can never switch to Android because they'll be left out of group texts. It's vendor lock-in of the highest order. Spectacular play by Apple, really. They guarantee switching to Android is painful, you risk losing business deals and messages from friends. I doubt it's legal, but for now they are getting away with it.
I've never had a problem with mixed Android/iOS group messages and media with iMessage. I've made no special effort to get it to work. It's seamless. Am I doing something wrong? Or right, rather?
Now, back when I used Android I remember Hangouts ruining everything it touched and I had to switch back to the deprecated Messages app (which was completely fine and did not need replacing) to fix it. Maybe the problem with the Android users on these group texts isn't on the iMessage side....
If you associate your phone number with an iMessage account, and then deactivate iMessage, Apple will just silently stop delivering group iMessages to you. You won't notice and your friends won't notice, they'll just stop coming.
If you unregister your number from iMessages, group texts switch over from iMessages to non-iMessage as soon as you send a message that has a member in it that is no longer iMessage.
This has not been my experience. I have some very long running group messages that switched over automatically when my brother switched from iPhone to Android.
When you switch from an iPhone to an Android phone, other people's iPhones will continue to send you messages over iMessage, which your Android phone will never see.
That's true, but if one of the people in an existing thread deactivates iMessage it will stay as an iMessage group chat and silently fail to deliver to that person.
Even now with Fi, I experience delays in delivery of SMS occasionally. I don't do SMS normally and most of the time I receive SMS for verification codes. A delay is annoying for that purpose.
At the time that I switched, the Hangouts app was having some difficulties of its own. The biggest issue I had with it is that Hangouts would try to upgrade me from an SMS chat to a Hangouts chat with someone, when the recipient was an infrequent or Gmail-only Hangouts user. Google would recognize their number and send Hangouts messages, they wouldn't see the messages on their iOS device because they didn't have a Hangouts app, so to them it would seem like I had stopped responding.