The construction is probably the biggest difference, and you can see that right away. While the Zulu 3 has almost no plastic in it, the Sierra is made from a fiber reinforced polymer. This is partly why the cost of the Sierra is less. The ANR of the Sierra, while very good, is not quite as good as the ANR of a Zulu 3.
What is the difference between Lightspeed Zulu and Sierra?Peter Fleming