im currently driving a mazda astina 1.6 and it is a fun car to drive. engine runs really well and handling is good.
Pro for astina: 4 doors, bigger boot, better acceleration at high speed, cool headlights
Pro for satria: less fuel consumption (i think), cheaper road tax, cheaper to repair cause its proton, more after market products as its more common
Personally i think the mazda will be more fun for you to drive, i test drove a satria and it didnt feel as good when compared to mazda.
Hope my opinion helped