The Bitmap uses a new bit crushing algorithm that was designed to add a little grit and warmth in the 8-16 bit range, like classic samplers.  It's a subtle effect, but the Bitmap is not just dropping the lower bits.  At more extreme settings, it is tuned to maximize sustain without sputtering noise after quick note releases.  The Bitmap does fractional bit reduction like the Tonecore bitcrusher did.  Overall, the bit reduction is warmer and less grainy.  The Bitmap's input and output gain are adjustable to make it easier to achieve consistent volume.  The input gain switch can also be used for saturation.

The response of the sampling rate (freq) knob has been tuned to make it easier to dial in useful settings.  The modulation mode has a fixed range that sounds good in most situations.  The Bitmap has fewer modulation options than the Tonecore module, but the addition of a CV-compatible expression pedal jack allows you to use an 8 Step Program or modular synth for extra control.

Finally, the Bitmap is mono in/mono out.  The Tonecore module could do some cool feedback tricks using a stereo dock.