hi members

i am converting a knee mill to a 4 axis cnc and i have been looking at different controller software for my conversion and have chosen to use linux cnc ,not so much thats its free but from what i have read it also looks to be very capable, my question is how hard is it to learn linux cnc, i have some programing knowledge but know nothing about g code
and further am i missing other software out there that is as capable and easier to learn as linux cnc that members know about,i have also read that mach 3 is limited when it comes to servo drives ,is this correct

Also if i was to use linux cnc what motion control board would be best for this application considering i want to control spindle speed using a vfd and linux cnc so the motion board would have to have enough inputs and outputs for limits and homing switch as well as other outputs like lubrication and vfd , also be able to drive a 5th axis, any help would be very appreciated


kind regards wayne