UCCNC is not included with the UC400ETH. It's an additional $60.
Both have their pro's and cons.
I've been told that the Acorn probably has better motion, and can run smoother and faster in some cases.
Virtually all hobby controls are step/dir only. The exceptions are Linux CNC with an analog control board, and Mach3/4 with an analog control. Most people only use analog control when retrofitting older machines with analog servos.
You can get one of those relay boards from Amazon for $10, and use them with any system.