Although both have square shapes, the actual shape of the driver and recess is different with each. All Robertson bits could be accurately described as having a square drive, but all square drive bits cannot be accurately called Roberson.
For anyone interested in learning more about screws and screwdrivers, I'd recommend the book One Good Turn by Witold Rybczynski.
I've always been a big fan of Apex bits, they're manufactured in the US. The steel they use is a lot tougher than the average bit so the life is 2-3 times the average life of a normal bit.