For two years, Apple Computer Inc.’s iPod has reigned supreme among hard-drive music players, both for Windows and Macintosh users. Now the competition is getting serious.

Just in time for holiday wish lists, Samsung is launching a 20-gigabyte player co-branded with the relaunched Napster service. The YP-910GS is priced at $399 — the same as Apple’s 20-gigabyte iPod for Windows and Mac computers.

But that’s not the only similarity. The Samsung unit has roughly the same dimensions and weight as the iPod. Both gadgets are dominated by a small liquid crystal display and navigation controls around a large center button.

However, to Samsung’s credit, its new player isn’t just another iPod copycat.

It has a line-in jack so it can record by itself. It can tune into and record FM radio stations. And, with an included antenna, it can transmit FM signals, allowing its music to be picked up by any nearby radio, such as a car stereo.

Navigation on the Samsung unit, which can hold 5,000 songs, is more complicated than on the iPod. The control to skip forward and backward is on the right side and moves up or down, not the more intuitive left or right. Volume is controlled by the front’s large button, which also is used to move between on-screen selections.

The iPod, by comparison, is much simpler: All the important buttons are conveniently — and intuitively — placed around the jog dial on the front of the unit.

The Samsung’s battery life is excellent, with the player running continuously for 10 hours as promised. It lasted about three hours less when transmitting full-time via the antenna. The latest iPod, by comparison, runs for about eight hours before its battery must be recharged.

Though Samsung has long been active in the portable digital music player market, the Napster unit’s built-in software is lacking. Play lists, for instance, must be generated on the computer. I could find no way to create them on the player.

Samsung's player has the same dimensions and weight as iPod, but offers more functions. Its price tag is 99.

Also, there was no easy way to play the entire library without first creating a play list on the computer, then transferring it to the player.

As its Napster name suggests, the player supposedly works best with Napster 2.0 music software, which became available to the public Wednesday. I found the prerelease version to be somewhat buggy, especially when transferring songs via the high-speed Universal Serial Bus 2.0 cable.

I tried loading nearly 1,700 songs of varying lengths in the MP3 and Windows Media Audio formats. With USB 2.0, songs transferred very quickly. But when I switched my computer screen to a view that showed transfer status, the program froze after several hundred songs. The problem occurred repeatedly.

The Samsung device also works with Microsoft’s Windows Media Player, which is more reliable.

Beyond music, the Samsung-Napster player can be used to store regular data files.

In my on-the-road tests, I found it worked well at the gym despite a sticker that warns against exposure to excessive force or moisture.

It also picked up radio stations with no problems.

Its low-power FM transmitter broadcasts in five frequencies, from 88.1 to 89.5. The key is finding one that’s not being used by an actual station, whose signals cause static.

Locked away in my garage at night, the Samsung’s signal sounded very good, the equivalent of regular FM radio. On the road in the daytime, with competing signals, there were noticeable cracks, pops and other static. The sound quality was about that of AM radio.

A few other oddities cropped up during regular usage, including the occasional odd pause during a song.

Like the iPod, the Napster player can be upgraded via downloads from the company’s Web site.