RepRapPro was using for all its machines a board equipped with a 32 bit arm processor, the Duet V0.6 then V0.8.5 (same processor as an Arduino Due). A delta printer requires much more calculation power than a cartesian and 8 bit boards are struggling to operate deltas. Typically, you cannot use a LCD screen on a delta with a 8bit processor controller, as it requires too much computing power.
So a 32 bit board is for a delta a major improvement. Note that CoreXY printers may also struggle on 8 bit boards, especially if you have a LCD panel.
The Duet have evolved in a new version, the Duet WiFi and also a Duet Ethernet.
On the Duet, the configuration is also more simple than 8 bit boards, as the parameters are simply defined in a configuration file. All parameters are defined in files which are placed in an SD card. This SD card is also used for printing, which allow the printer to run in full autonomy.
Stepper drivers are on the board and motor current is digitally set by the board itself and can be modified during operation.
A web server is installed on the board and you operate the printer with this web server, through an Ethernet link, or if you don't have a router, through a Wi-Fi bridge. The printer is autonomous so if you loose the link, you cannot see the parameters but this does not stop the print. There is no local panel. A very complete touchscreen panel the PanelDue is sold by David Crocker and Think3DPrint3D. No simple panel is available nor seems forecasted.
Provided your network runs DHCP, the connection to the printer is automatic, simply calling its name (modifiable) in your web browser. Alternatively, you can configure a fixed IP adress. Note that on mobile device, you shall use IP address.
The availability of a very capable web server in the main printer board is unique and makes it the only real 'all in one' board. Others board are using an external computer, frequently a RaspBerry Pi to run the Octoprint Web server.
A major feature of the Duet is the fast transfer speed over WiFi or Ethernet at 500 to 1000 kB/sec, which is a very rare feature even on other 32 bit boards which rarely exceed 40 kB/sec. This allow the quick transfer of the G-Code file to the board SD card and improve usability as print is always done from SD card. This remove all the troubles caused by USB connexion. This does not prevent to send G-Code from web server for any adjustment, initialisation or other operation.
It shall be noted that the majority of Duet operates 'Headless' with no local screen or button, but with WiFi, phones or tablet could be used to control the printer if it is remote from the main computer.
Having such a capable brain in a low cost machine as the Fisher was unique on the 3D printer market.
It shall be noted that the main developments for the Duet used in the Fisher were not done by RepRapPro nor the board designer, but by independent programmers, the Delta Geometry and automatic calibration by David Crocker (DC42) and the Web server by Christian Hammacher. The original developer(T3P3) and David Crocker then joined forces to Develop Duet Ethernet and Duet WiFi and improve documentation.
The Duet had initially scarce documentation but this have evolved with Duet WiFi where you can find relatively exhaustive documentation (sometimes also for older boards) on Duet3D site.
An important information is also the calibration of the Analogic converter on Duet 0.6 and Duet 0.8.5, required to improve the accuracy of the temperature measurement. All my calibration shown that the theoretical temperatures were off by more than 10°C (this adds to thermistor inaccuracy). See https://www.duet3d.com/wiki/Connecting_thermistors_or_PT1000_temperature_sensors. This BOARD calibration is automatic on Duet WiFi and Duet Ethernet.
I developed a page on the configuration of the Web interface (obsolete)
Note that the Duet WiFi sold on AliExpress are NOT genuine, even if they show the 'genuine garantee'
Also on AliExpress you find boards labelled Duet 0.8.5 which are actually clones of Duet 0.6. And there is NO WiFi on the Duet 0.6 - No shame...
And these Duet 0.6 are sold on Aliexpress 134 Euros, while you can find Genuine boards for 85 Euros on https://emaker.io/product/duet-pcb/...
These clones prices are quite high and there is no point taking risks buying something else than the original.
Note that SAM processors do have internal serial numbers, so you can check the board origin by asking to Duet3D.