Zune HD goes on sale.

The music player had been available for pre-orders at retailers like Best Buy for weeks, but it’s now for sale on store shelves.  The new Zune HD touch-screen media player includes an HD Radio, a feature that’s drawn positive reviews.  “Microsoft stepped up the Zune HD’s FM radio functionality,” writes PC World.

It tells readers HD radio delivers “a cleaner sound quality” and offers multicast.  “Best of all, HD radio is 100% free,” the magazine says in its Zune review.

Microsoft wouldn’t have been able to include HD Radio in the Zune had it not been for SiPort’s development of a single chipset.   SiPort CEO Aiman Kabakibo says they worked “very closely” with Microsoft to overcome “tremendous constraints” in power, size and performance to put HD Radio into Zune.

Tech consultant Susan Kevorkian believes it was worth it, particularly as iPod adds FM capabilities. “HD Radio is a key differentiator for Zune HD,” she says. “We know from our survey research that more than a third of U.S. survey respondents identify FM radio as their preferred source of music.”  That makes it by far the most popular source of music overall.  Yet Kevorkian adds, “A key gating factor to consumer adoption of HD Radio — until now — has been a lack of compelling, competitively-priced devices.”