I personally prefer SATAM Robotnik over the games' Robotnik/Eggman. Both of them want world domination however Eggman is on good terms with Sonic and if needed will help him. SATAM Robotnik on the other hand despises Sonic with every fiber of his being. In the games Eggman doesn't really try to kill Sonic in the games unlike Robotnik in SATAM who constantly attempts to kill him. He created a machine that turns people into robots to be his slaves.
I like how Eggman in Sonic Forces leaned towards the more sinical and sadistic side of his character by capturing and torturing Sonic. Overall SATAM Robotnik was just a lot more menacing with his voice, eyes, power, and aura. You're completely entitled to disagree with me and if you have any notes feel free to tell me.