The biggest difference between the equinox and the solstice is that a solstice is the point during the Earth's orbit around the sun at which the sun is at the greatest distance from the equator, while during an equinox, it's at the closest distance from the equator. Because of this, one solstice is an extremely long day, and the other is an extremely short day. Comparatively, during an equinox, the days and nights are equal lengths.
