My wife had a Win 8 laptop that was chock full of viruses. I gave her my iPad and took hers. Cleaned up the viruses and installed a dual-boot with Ubuntu. Haven’t bothered with the Windows since. Ubuntu works fine for me.
I’d say “No” on the first question, to be honest.
I asked an AVAST tech about Windows 10. He said to wait a couple years until they got the kinks out of it.
i switched to Ubuntu as well and have had no problems. my laptop still has windows and will soon be upgraded to Ubuntu. so there microsoft.