As a newly-graduated mechanical engineer with 8 years of being on the TI-8(1|2|3) bandwagon, I bought a HP-35s six months after graduating because my co-worker would consistently get answers faster than me on his calculator. It's just faster to key in everyday things in RPN vs infix notation.
Agree - I like being able to just start putting the values in before I've figured out what needs calculated first. You can then shuffle them around and bring in value from further up the stack as they're needed, all while seeing intermediate results. That beats having to backtrack to add brackets, or saving to memory registers because your calculated value is the denominator or something.
One day I'll buy a macro/numpad with an LCD screen and run some kind of simple RPN for my desk.
