We are not familiar with the FX1GM so we can't say how it compares with that on the T100MD+.
The T100MD888+ has two channels of stepper motor controller that output pulse and direction and 2 channels of High Speed Counters (quadrature decoder). Both stepper motors and high speed counters support up to 10,000 pps. T100MD+ is primarily a PLC but can perform simple positioning control. However, it is not meant to be a substitution for high end servo motor controller which is a totally different class of control.