What are you using right now?
I was on RAMPS 1.4/5/6 and ended up going ReARM for 32bit. Then I got tired of Marlin’s flakyness. I went to the LPC port RRF and have not looked back. You can use a 12864 LCD like the Duet Maestro too.
I helped a couple of guys put RRF on their SKR 1.3’s too. It works too.
To be clear- is it equivalent to a full blown Duet board- no. Does it work- YES!
But, its hard for me to make a real comparison since I don’t own a Duet yet. But it made sense as an upgrade path to spend $30 to go ReARM instead of $130 for Maestro or $175+ for Duet2.
EDIT: You can also run this on an AzteegX and Smoothieboard too.