Like many other "Tekno-geezers," I believe the HP-35 calculator was a world-changing device. For me, it was freedom from sliderules and looking up values for functions in tables in the back of text books. The Hewlett Packard Company built impressive products that were on the leading edge of technology. It was empowering to be able to own a product made by the same company that built so many oscilloscope, analyzers and other sophisticated instruments that changed the way electrical engineers worked. To me, only Tektronix was in the same league as HP.

Today, Agilent is that company and Hewlett Packard is just another "me too" in the computer appliance business. I just purchased a 35S and it is a good instrument. But I bet if it had been an Agilent product, it would have been more innovative and powerful that it is. On the other hand, it probably would have sold for ten times it very modest $60.00 price as well.
And yes, just as computers have not eliminated the need for a pencil, they will not eliminate the need for a calculating device that you can pull out of your pocket to get quick answers to math problems.