I would not even attend an interview if it's not clear that I can work on Linux in that company. I was forced to use Windows daily for 8 years. After that I got a chance to move to Linux development. I'll never want to go back. Not that Linux is free of problems. But the feeling of being in control cannot be replaced. If I don't accept the wart I can patch it. If I don't want to invest the effort to patch it I live with it. The choice is always mine.
I've used desktop Linux for a long time, and it's really, really good now. I cannot even remember the last time something didn't just work out of the box(probably my laser printer).
Still working on the last part. Parents buy and use tax software each year for some odd reason, and I don't feel like even trying to navigate through WINE.