They're almost identical. The main difference is Prius uses low speed high torque MG2 and Camry hybrid uses high speed low torque.

Prius's MG2 drives the ring gear directly. OTOH, the MG2 of Camry hybrid drives the ring gear through a reduction gear as same as Highlander, RX 400h and GS 450h.
The max speed of the GS 450 is 250km/h, so it has two speed reduction gear to meet the wide speed range.

Ken@Japan