Remember being sat in the pub circa 2000 and using my Psion Revo connected via my Nokia 7110's IR link to clear some disk space on a server and avoid having to return to the office.
I still have my Revo in a drawer though. As of five years ago, it was still able to power on. I found the form factor of this device to be great. It was light, energy efficient, actually pocketable and could actually be used for serious productivity in a way that modern phones cannot: I was touch typing all my courses on it with no issues. It sad how Psion / Symbian failed to thrive in the early 2000s.