I'll echo Mr. Rigby's comments about RPN. I've used a HP12C for over 20 years and believe it to be a more logical approach to calculations. Moreover, it only takes about 30 minutes of tinkering with the calculator to get used to the concept.
But, there's another, hidden advantage to the HP12C. When others in the office find that there is no key on it with an equal sign, they quit asking to borrow it. While other calculators I've had seem to have disappeared, I've been using the same HP12C all these years.
Good luck!