The Hackberry Pi is a handheld Linux terminal similar to the Clockworkpi uConsole. Its key feature is it uses left over keyboard stock from the old Blackberry phones of yesteryear.
You can read my comparison to the uConsole here, and here are 10 things to do after you get your Hackberry Pi 5.
The Hackberry Pi currently comes in two flavors, one based on the Raspberry Pi Zero 2 W (RPi 0) and one based on the Raspberry Pi 5 (RPi 5). Both devices have a 4" 720x720 screen, both have a battery life of 2-3 hours depending on what you are doing with it and both cost roughly the same, before you purchase the Rasperry Pi you need to power it.
The RPi 0 version is a rather limited device, primarily because the RPi 0 is a limited device. It has 512 MB of RAM and runs at 1 Ghz. You can run a desktop environment (DE) on it, but you will not be happy with the performance of some application like Firefox, Chrome or well anything more complicated then a text editor or calculator. The RPi 0 was not designed to be a desktop computer, it was designed to be a hopped up micro controller, so it does not do well in this area. However, if you are a command line junkie, this limitation will not bother you in the slightest.
There are plenty of reasonably good replacements for GUI applications that run in text mode. Alpine and W3m for email and web browsing, cmus and mpv for playing music and videos, and wordgrinder, sc and tpp replace LibreOffice (mostly? I guess). While you will find these applications limited compared to their GUI counter parts and the learning curve a bit annoying, once you get use to them, they are usable and have a certain minimalist appeal to them.
The biggest problem I had with the RPi 0 version is the wireless does not work well. This is because the front cover is made of aluminum and blocks the signal. It seems some people have better luck than others, I tried two different RPi 0's in mine and both could connect to my router, but neither could actually communicate with it in any meaningful manner. I had several USB wifi dongles laying around and I just plugged one of those in to solve the problem.
Edit: I did eventually get the on board WiFi working. I wish I could tell you how I did it, but I cannot, it just started working one day.
The RPi 5 version is a much more usable device, depending on what RPi 5 you buy. If you get the 4 GB version, you will want to stick with a light DE and stay away from Gnome or KDE. If you get an 8 GB or 16 GB RPI 5, you can pretty much do anything you want with it. I bought the 8 GB version and it has handled everything I have thrown at it so far.
The big, I do mean big, advantage the RPi 5 version has over the RPi 0 version and the uConsole for that matter, is the PCIE connector on the board. The designer of this device left room to mount a M.2 hat on the RPi 5 that provides access to the PCIE connector. It just so happens Waveshare makes such a hat. This hat not only provides an M.2 slot, it also provides active cooling to the RPi 5, something it really needs. You can mount just about any 2242 / 2230 M.2 card into it, like a fancy A.I. accelerator, but we all know the primary use case is mounting an NVME SSD card to it. SSD storage is faster and more reliable than an SD card. This by itself, makes this the stand out product among hand held terminals.
I only really had one issue with this device, when I first put it together I couldn't get video to save my life. As an assembly tip for those who have not purchased one yet, if you assemble it and don't get video after waiting 5-10 minutes, chances are good you didn't line up the GPIO contacts properly. Remove the cover to the RPi 5 and remove the standoff screws. If you did not remove the piece of plastic that came inside the case, take it out now and throw it away. Now place the Raspberry RPi 5 back in and put the bottom left stand off screw in first, it is the one closest to the GPIO pogo pins, tighten it down and then back it off 1 or 2 turns. Then put in the right stand off screw, tighten it down and then back it off 1 or 2 turns. The Raspberry Pi 5 should have just a little bit of wiggle, move it around until you feel the pogo pins snap into place, you should feel it click. Then tighten both screws down and put in the top two screws and tighten them down. Put the cover back on and try to boot it up again, you should get video.
Both of these devices share the same keyboard and I do need to talk about it. The keyboards take some getting use to, not just because they are hideously small, but because the keyboard is a challenge to use. It takes time to figure things out and learn all key combinations needed to do even basic typing. I can see how this keyboard was considered innovative back in the early 2000's, but there is a good reason why they were replaced, they are awkward to use. Part of the issue was, I am Gen X and did not grow up thumb typing like the younger generations did. I have adapted to it, though it has been a struggle.
Overall, if you are considering the purchase of one of these devices, I would go with the RPi 5 version, as a real functioning tool, it is the better choice. The RPi 0 version is really not much more than a command line junky toy. The RPi 0 version does not do anything the RPi 5 doesn't do better and its not that much cheaper. It's only advantage is it is smaller and lighter, and it will actually fit in your pocket.