When it comes to describing a product or service as the "market-leading" option, there are plenty of synonyms to consider. "Dominant" is one such alternative, implying a level of superiority over competitors. "Top-rated" and "premier" both suggest a high level of quality and customer satisfaction, while "established" suggests a well-respected, long-standing presence in the industry. "Flagship" implies that a product or service is the most important and influential within a company's lineup, and "pioneering" suggests that it was the first of its kind to hit the market. Overall, there are many effective ways to convey the idea of being a market leader without using that exact phrase.