I have similarly been looking for a modern Sharp Zaurus replacement. But the Pyra (and the Pandora before it) does not make a good PDA.
For one thing the dimensions: it is a real brick and I don't understand why that is in 2016. All the flip-top Sharp Zaurii SL-Cxxxx were at least 5mm slimmer, and they were made a good ten years ago.
Then there is the keyboard, which is pushed all the way to the bottom edge, which makes it difficult type when handheld. It is clearly optimized for gaming, with prominent space given over to joystick controls. It lacks a bottom row containing a spacebar, which makes for awkward typing.
To put this into context. The Sharp Zaurus SL-C3000 was released in Japan in 2004. It was a Linux computer with a 3.7" touch display, 4GB hard drive, USB port, SD and CF card slots, 3.5mm jack, infra-red port, built-in speaker that fit in a case with dimensions 124x87x25mm.
Even though the Pyra has a 5" display, its dimensions are no less bulkier at 140x84x29mm. I would have expected a lot more progress given the hardware advances made in the last 10+ years.
Heck you could put something like the Intel Compute Stick or the Zotac ZBOX PI220 in a case, add an LCD and battery, and end up with something more compact and powerful than the Pyra.
Looking into it some more, it is indeed mostly the battery.
It is 3x the capacity of the C3000, and runs the full width of the Pyra.
Never mind that they also made use of the thickness to fit 4 shoulder buttons for gaming (or other things), and two full size USB-A ports (one of them claimed to support ESATA as well via an adapter).
There is no doubt the Pyra is much more capable than early 2000's palmtops. It has built-in wifi, bluetooth, HDMI output, sensors, etc.
Nevertheless, I am sure we can all agree that its design does not make efficient use of internal space. There is a lot of room for improvement to make the device more compact. Yet this does not seem to be a priority for the creators or many of the end users.
For comparison take a modern device that is comparable in dimensions like the Sony Xperia Z5 Compact at 127x65x8.9 mm. Sony fit an LCD and 2700mAh battery in just 9mm of thickness.
As for the large battery, it seems gratuitously huge. Do we really need 6000mAh in such a device? This is like 2.5x a typical phone with a comparable processor.
This is a great device for some use cases. But it is not practical as a PDA.
I just discovered more official Pyra dimensions, which show the device 3mm thicker than what I originally cited. According to the technical specifications [1] the dimensions of the Pyra are 139x87x32mm.
https://pyra-handheld.com/boards/pages/pyra/