Almost 39 million people used a Roku device at least once in the month of July, representing 23% of all connected TV users, the market research firm said on Wednesday. Roku pulled ahead of Google’s Chromecast, which was used by almost 37 million people, or 22% of the market, but had been the leader the last time eMarketer surveyed the scene back in October. Amazon’s Fire TV ranked third, with almost 36 million users, followed by Apple’s Apple TV at just 21 million users.

One of Roku’s advantages is that it is not affiliated with a content or device offering, like Google’s Android phones or Apple’s iOS. That makes it easier for Roku to strike deals with a broader array of content partners, Paul Verna, principal video analyst at eMarketer, says. “That expansive strategy, combined with the company’s broad selection of connectivity devices at various price points, has put Roku at the head of the pack,” Verna said in a statement.

Roku has hired two investment banks to start planning for an initial public offering that would value the company at about $1 billion, the Wall Street Journal reported two weeks ago. The company had 15 million active accounts as of the end of June, up 61% from a year earlier, the paper reported.

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Apple’s (AAPL) problems include having fewer content offerings and charging higher prices. While Roku, Google (GOOGL) and Amazon (AMZN) have entry-level devices priced at $40 and under, the cheapest Apple TV is $150–and hasn’t been updated in almost two years.

“Apple TV has been held back by the absence of a compelling content offering, a lack of support for increasingly popular Amazon video content, and a much higher price bracket than its competitors,” Verna said.

While the market for Internet set top boxes continues to grow, fewer homes will have Blu-ray players in coming years, eMarketer forecast. About 19% of homes had a disc player last year, but that is projected to decline to under 15% by 2020.