Just over 1 cup water to 1 cup rice (pretty much 1:1, plus the residual moisture from rinsing) for most white rice. 4 minutes at pressure, but probably comparable in practice. (have to wait for it to come to pressure and lose pressure after)
Really, it's been about consistency for me, but I've only compared to a basic Aroma rice cooker. I really liked my rice cooker, but side by side the IP was just better. Seemed like the grains were more consistent all the way through, like the rice cooker grains had a bit of hardness/density at the center and weren't as fluffy, from what I remember.