*Spoken by someone who clearly doesn't use RPN. The speed advantage of RPN doesn't come from the number of keystrokes needed (even though RPN does take fewer), but with the ability to enter the equation from left to right, start to finish, no matter how many embedded factors there are. While with non-RPN you must evaluate the equation to even know where to start entering and then keep track of where you are in your head.*

Spoken by someone who clearly doesn't use modern non-RPN calculators. The speed advantage of conventional notation calculators comes from the ability to enter calculations froms start to finish exactly as they are written down on paper. No mental gymnastics required to translate what's written to what you need to punch into the calculator. And you can put the entire equation into one line, again, greatly simplying things.

Now, back in the day when calculators had only one line displays that could only display numbers, RPN was a great advantage. But in the modern age (meaning post ~1989 or so) calculators (like the TI-81) have multiple lines of display and can display the full set of alpha/numeric/symbols. So no need to keep track of anything in your head, it's entered in as written on the page, and displayed right there on the screen.

*I try not to make such blanket statements on /., but I simply do not believe this. You may have had a friend at MIT, but there isn't any way a non-RPN calculator is as fast as an PRN calculator on any equation more complex than 2 + 2.*

Well first off, I'll assume you're talking about a RPN calculator, and not a PRN calculator. Although a PRN (or pr0n) calculator would be very cool, I think it would make getting any real work done very difficult.

So why don't we go back in time together to the mid-90's, and you and I can hammer through some hard-core electrical engineering problem sets together. You can have an HP-48, I'll take a TI-81, and we'll see who wins at the 'ole plug-and-chug. What you probably haven't taken into account, is that you can't submit your problem set written out in RPN. So the time and errors that transpire in that back and forth translataion between the problem set and your calculator will more than compensate for what ever advantage in theory RPN may have.