Personally, I still have ember apps from 2015 that are now on v3.6 and have had pretty much painless updates. I have used react professionally, but used Ember when starting a new app this past fall. I just trust them to keep things stable over time and I don't have the ability or desire to spend a lot of time bikeshedding my setup. It's not glamorous, but I do get a lot done and can keep things working for years.