Western Astrology is also called Tropical Astrology. It uses a system of twelve signs which are tied in to the seasons. First day of Aries = first day of Spring, for example, first day of Cancer is the first day of Summer. Centuries ago, the solstices and equinoxes lined up with the start of the constellations, and so the signs and constellations were one and the same. Over time, though, the two have shifted almost one sign apart.

Vedic or Sidereal Astrology uses the constellations, not the signs.
So the first day of a solstice or equinox does not coincide with the beginning of any particular sign.

The difference is in perspective. But if you have your ascendant in one sign in Western astrology, it will probably be in the previous sign in Vedic...because as I mention, the two are almost a sign apart.

The readings do differ, and so do the philosophies behind most of the interpretations in each system.

As far as accuracy, I find I can read a Western chart but not a Vedic one, but know some Vedic astrologers who can give strikingly accurage readings. I think it is a matter of your personal perspective.

Zane