I purchased this computer for a Commodore 64 and Amiga emulation project and have been very pleased with the hardware. The form-factor of the Pi/400 is compact, light, and comfortable. The unit runs quiet due to no mechanical parts, and also does not get hot due to the enlarged Raspberri Pi/4 PCB and heat spreader. Installing software is straightforward, but be prepared to compile sources for software that doesn't release binaries for the Raspberry Pi OS (Debian 10); this is very common in the Linux community.
I purchased the Pi/400 as part of a VILROS kit and am very happy with the effort put into the kit and its documentation. I received a 32GB SanDisk SD card, 5V 3A power supply, micro HDMI->HDMI cable, BlueTooth/2.4Ghz mouse, and carrying case; more than what I needed, but ideal for the price.
Please note that during the installation of Raspberry Pi OS, the process will ask you to update to the latest packages/OS on the system. Doing so broke BlueTooth connectivity and thus I couldn't use my mouse without occupying one of the three USB ports. After a bit of research, I discovered that the updated Bluez package introduced a regression that disabled BlueTooth. Fixing this was as easy as reverting the package to the previous version with the following command:
sudo apt install bluez=5.50-1.2~deb10u1+rpt2
Again, this is not an issue with the hardware or any service provided by VILROS, but rather with the ever-changing software landscape of the Linux community.