Well, we do limit our discussion here to EMDR related questions. I'll see if I can put your question in a different context, namely: how are EMDR and somatic psychotherapies the same or different.

Similarities: EMDR and somatic psychotherapy (I'm mostly familiar with Somatic Experiencing) have in common that the person tracks their experience in the present moment, with the therapist guiding the tracking. In the tracking, the material is metabolized and released. Both rely on resourcing the individual.

Differences: EMDR is top down, namely a cognitive target is selected, as well as bodily held material. SE is bottom up, beginning with the body as the biological substraate of experience. EMDR is faster, SE is gentler. EMDR starts at the beginning and goes until the target is neutral. SE moves back and forth between resource and trauma, just nibbling at the trauma. EMDR dives in.

SE requires superior levels of empathy and resonance; EMDR requires empathy but does not require the same level of it to maintain the process.