Based from my own experiences, I would have to say electronic products are the most fun and rewarding because you get to design everything from the inside contents to the outside aesthetics and ergonomics for all kinds of environments and conditions.

I was also fortunate enough to design more than a few peripherals back in a day before it was done by anyone else, yes even before cell phones were invented. Like this tilt able mounting holder that the device snaps into and also connects instantly to external power, antenna and communications with other electronics.

As well I've done a few firsts in the enclosure designs, the mold tooling, circuit board mounting, connections, keyboards, displays and how it all went together from manufacturing to packaging. I even got to name the products and design the graphics' artwork.