I've used RealCalc for a few years. I paid a few bucks for the "plus" version. It hasn't been updated in years, but that's fine with me because it just plain works.
Same here. I have to sheepishly admit that I prefer infix notation, and RealCalc reminds me of the cheap Casio scientific calculators that I still use.
The first thing I look for in a calculator is that you can enter numbers in scientific notation without hitting a Shift button.
