I owned one of these, not as good as a Psion 5MX that preceded if year before. Sure this was an all in one but no, always laughed at the ariel and the thing felt like you could almost use it as an ice-pick with the ariel folded down and the unit closed. But hey, was neat - just the usual issues of these open/close designs was the ribbon cable to connect the screen - those always seem to fail outside warranty period.
But crux was, this was too dam expensive and heck a few years later Blackberry would have it's moment and that did more for the market than the Nokia communicator ever did. Heck the IBM Simon did more than the Nokia did for pushing things or about the same lack-lustre uptake.
FWIW I got my communicator for free from a friend who orded one and got two with the company failing to take back the second one in a period of time that made it legally his (he notified in writing so was 3months, maybe 6).
I would also ad the Sony P800 was more game changer as well than the nokia communicator. Also owned that and for the era - pretty darn good.