That's a no-brainer. Most of what the Windows calculator can do, I can do in my head. For anything mildly challenging, I reach for my trusty HP-35s. I may be biased, but my first calculator was an HP-67, and I wrote immensely complicated programs for that thing that got me through engineering final exams. My favorite was a huge one that would solve the roots of a 20th order linear control system transfer function. I've tried others, but there is nothing as efficient as RPN for complex calculations.
Will Rogers never met me.