If we're going to discuss professions let me say I manage an IT team comprised of 35 people. I manage security for intranet and Internet. My team develops and tests for both in all four major US platforms. Which brings me to why I have an SGS7, I needed it for testing because the SGS5 we had was rendered useless for our testing due to Lollipop. I Bieber you might see a pattern.
If I have been lucky then I have had a stretch of luck running all the way back to 2009. No issues at all with any update since my 3GS which still runs. Slow, but it runs. Better than my Note 4, probably.
It appears you have terrible experiences with your iPhones. I happen to have terrible experiences with my Samsung devices. Which is why I skipped buying the SGS4, SGS5, SGS6, and Note 5. Would have slipped the SGS7 BUT REALLY NEEDED a device for testing and rather than spending huge amounts of energy and time in the procurement process at work, since the device won't ever touch the network, I bought it to use for testing of external responsive design pages.
Oh and I would never go to a third party for repairs. I only go to Apple. I've got Apple Care Plus. I didn't use it on my iPad because frankly if I do then that takes away my excuse for buying a new one. HA!!!
If you want to discuss Android vulnerabilities, we will be here a while.
https://web.nvd.nist.gov/view/vuln/search-results?query=Android&search_type=all&cves=on