Compatible with both Macs and PCs, the 20 GB iPod can store over 300 hours of music (5,000 tracks of length 4 minutes). This capacity is based on music encoded in 128 Kbps AAC format (see below for an explanation). This capacity should be enough for most users, but if not you can opt for the Apple iPod 40GB with double the capacity.

A full battery charge is enough to play music for up to 12 hours. This is probably the iPod's biggest weakness, as other MP3 players offer greater capacity, but it's still enough for most people if you charge it overnight. The battery can be recharged either from a normal power socket (using the mains power adaptor supplied) or via a computer (using the USB 2.0 cable). Recharge time is around 4 hours for a full recharge, or 2 hours to 80% capacity. Battery charge levels are shown on the main display screen.

The iPod supports both MP3 and AAC formats. Music in AAC format can be compressed smaller than the MP3 format with the same quality, so is the best format for storing digital music. The quality of the music depends on the compression factor - the greater the compression, the lower the quality. The iPod supports compression rates from 16 to 320 Kbps. In addition the iPod supports the Apple Lossless format, as well as WAV and AIFF.

The iTunes software that accompanies the iPod provides an easy way to create and manage your digital music collection on a PC or Mac. With iTunes you can transfer music from an audio CD into digital format. iTunes supports a range of formats including MP3 and AAC and you can control the quality/compression level. The Apple Lossless encoder provides a sound quality that is indistinguishable from the original. One key advantage that the iPod offers over other MP3 players is a FireWire connection as well as USB 2.0. FireWire is a connector often found in digital camcorders and provides for super-fast data transfer. In fact, using FireWire it is possible to transfer the contents of an entire audio CD in just 5 seconds! Finally the iTunes Music Store lets you browse, buy and download over a million tracks online.

The iPod is a very good, easy-to-use MP3 player and has lots of great features. However, as our user reviews below show, it does have three downsides. Firstly, it's not the most durable electronics product and has a tendency to freeze or shut down. Often users experience problems after about a year of use. Secondly, the battery life isn't the best, and tends to get worse over time. Thirdly, the user interface slows as the memory gets filled up, and it can be quite slow to respond when nearly full. These problems are not universal, but many users report them, and you shoiuld be aware of them when making your buying decision. The 5th generation iPod improves on the 4th generation in a number of ways.

Features of the Apple iPod 20GB M9282B-A include:

• Keep up to 5,000 songs in 128Kbps AAC format in your pocket
• Use it with Mac OS X or Windows 2000/XP
• Take it everywhere--it's only 158g (5.6 oz)
• Find songs fast with the Apple Click Wheel
• Listen longer with up to 12 hours battery life
• Shuffle songs in the main menu
• Play MP3, AAC and Apple Lossless
• Jog without fear--25 minutes of skip protection
• Save multiple On-The-Go Playlists
• Adjust speed for Audiobooks
• Sync and charge via included FireWire or USB 2.0 cables
• Use as a portable hard drive - take your files with you
• Accessories not included: dock, remote, carry case