Different Zodiacs: Which One is "Better"?
First of all, many people believe that whereas Western astrology uses the signs of the zodiac, which are equal 30-degree sections of the ecliptic, Vedic astrology uses actual constellations. This is wrong: Vedic astrology also uses a zodiac made of equal 30-degree signs, but it uses the sidereal zodiac. The difference is in the starting point. The tropical zodiac used in Western astrology starts from the point of the vernal equinox, which is easily defined astronomically, and so tropical zodiac is well established, clear and unambiguous.
In contrast, there are several different opinions regarding the starting point of the sidereal zodiac. The difference between these two zodiacs is called Ayanamsha, and there are several different Ayanamshas in use by different astrologers. The most popular and, as far as I know, officially approved in India is Lahiri Ayanamsha.
Technically, sidereal positions of planets are calculated from their tropical positions by subtracting the value of Ayanamsha for that particular date.
There also seems to be an ongoing argument regarding which zodiac is better, or truer. I believe this argument is as unproductive as an argument about which religion is truer. In addition to the already mentioned tropical and sidereal, there is also draconic zodiac, starting from the Moon's North Node. There can be some other zodiacs I haven't heard of. The tropical and the sidereal are simply most popular, as they are used by two established astrological traditions.
This might be difficult to comprehend from our limited perspective, but all zodiacs are valid, as far as you use them consistently. Our world is akin to a hologram: you can look at it from different angles, and you will see something different, but none of the views will be truer or better than any other.