I used it a lot, not through Google’s gchat stuff, I ran my own XMPP server. It worked really well, I used the OTR encryption plugin in pidgeon. My work also used to use xmpp for internal chat within the company, however they switched to matrix like 5-6 years ago. Something I’ve since done personally too.
I like XMPP a lot, it worked well, including it being federated.
My last phone I kept for about 5 years. I had two issues:
fortunately there was a local shop who’d replace the battery (it wasn’t a fairphone so I couldn’t do it myself). If it wasn’t for the software support I’d have gone that route and would be still using it now. It worked perfectly well for my use case. Unfortunately, I ended up retiring the phone and getting a new one.