So both Klipper and Marlin+Octoprint use a Pi and an arduino (in simplified versions, the SBC and the MCU can be any boards but I’ll use those brand names to make it easy).

Marlin uses the Pi to display the web interface, then sends the gcode to the arduino. Then the arduino does the math to convert the gcode to motor commands. Gcode.

Klipper uses the pi to display the web interface, but it also takes the gcode and converts it to motor commands in the pi and only sends those simplified motor commands to the arduino.

So with Klipper the arduino doesn’t need to convert gcode which is a pretty intense computation. Also, gcode is actually pretty heavy to send vu serial over usb in Marlin and often the printer can print faster than the gcode can be sent. Which results in hang ups in the print, the printer pauses, especially in a print with a lot of curves and printing fast. Klipper can use the full power of the pi to make intricate motor commands, fine tuning acceleration and all to avoid vibrations (input shaper, it even uses an accelerometer sensor to refuse vibrations making cleaner prints and quieter printing)

Other benefits of Klipper, settings don’t need to be flashed to the arduino, they are saved in a text file on the pi. Changing Config is a simple text edit, then reboot to apply the changes. You can edit the settings right in the web interface.

One of the down sides of Klipper was that you had more functions in Octoprint with plugins, that’s not true anymore. You have many plugins compatible with Klipper with Timelapse exclude area, remote access, Obico (the spaghetti detective), and so on.

The web interface is much lighter and responsive than the bulky Octoprint. Octoprint was an afterthought while Mainsail was purpose designed for Klipper.

I used to run Marlin and Octo and hated the experience. Since I tried Klipper I can’t go back.