When I arrived at my friend's house she told me all about the virus they had spent the last couple of days removing after her husband upgraded her computer to Windows 10. Their theory, after literally hours on the phone with customer service, is that it was already there in Windows 7 but just didn't make itself apparent until the upgrade.
"You have to talk to Dave, he's had it!" When we talked to Dave I was surprised, he really had had it. Even though he has a long history of preferring Windows, he was telling stories about all of his friends who had switched to the Mac and stories of his friends who wished they could but had some proprietary software preventing them from doing so. Listening to him talk, he was sincerely ready to make the switch, at least for his wife.
The one minor stumbling block was Quicken for the Mac which we talked about as if it didn't exist, but I just checked and appears that they've started selling it again. It turned out not to be a showstopper for other reasons.
In this case, they decided that a 27-inch iMac was the best option. It was the closest computer to what she already has and she has no desire to have a laptop.
The Calm After the Storm
The people I know who have decided to try a Mac are so calm and happy. The stress isn't about switching to a Mac, the stress was the days and weeks before that pushed them into the decision.