Rio Nitrus review

Rio's MP3 players are both hard disk-based, but the smaller Nitrus uses a Microdrive. Both ultimately function in a similar way, though there are key differences beyond size and capacity.

The Nitrus gets our nod as the mini hard disk player of choice, but only just. Mini hard disk players are somewhat difficult to decipher at present. They're trapped between large-capacity players, which are ever decreasing in size, and the ever-increasing capacity solid-state players. However, there are advantages of mid-range capacities. Searching through a vast music library on your computer is one thing but it's a pain when you've a relatively tiny screen and limited navigation buttons. With its 1.5GB capacity, the Nitrus offers a good balance of storage space and easy navigation. If you still need convincing, the iPod mini hullabaloo shows how this combination of capacity, size and price can be very attractive.

With the smaller hard disk-based players, capacities of 1.5GB and 4GB are on show this month, but the Nitrus is stuck with the former. Using a reasonable compression level, it could still hold between 20 and 30 albums. Plus, the fact that hard disks limit battery life means you'll be able to update tracks when the player is recharging, so the size difference becomes less significant. For these reasons, the Nitrus was the best of the bunch.

The others were close behind but had niggles which prevented us recommending them. The MuVo2 offers great value, but navigation was difficult due to the tiny screen and poor controls. We'd also question the build quality. Philips' HDD060 sounded great but navigation and synchronisation software were both poor. The iPod mini was good but only slightly smaller and slightly cheaper than its 15GB counterpart - you'd be silly not to opt for the higher capacity.

Ultimately, it's the way in which both Rios organise files that makes them so desirable. They rely on ID3 tags - not our favourite method - but one that, on paper, holds many advantages. You can find any song according to any aspect of it - artist, title, genre, date and so on. However, if your existing MP3 collection is anything like ours, you'll have a fair few tags missing, meaning you'll have to trawl through vast lists of songs (many beginning with the same track number) to find what you want.

However, the Nitrus and Karma's integration with the excellent Rio Music Manager means your music library can be quickly organised. Bulk tags can be added so finding the song you want soon becomes simple. It should also be noted that Windows Media Player can be a great help in automatically adding many tags to your songs - by checking databases on the Internet - though this doesn't always work reliably and requires some fiddling with settings.

Rio Music Manager also sports some nifty synchronisation features. You can choose how much content you want replaced, whether you want your most played, least played, oldest, newest or random songs deleted, added or replaced. This can happen manually or whenever you connect the player. The software also updates itself and the player's firmware automatically via the Internet.

Onboard navigation for both the Nitrus and Karma is superb. The RioStick multidirectional button is intuitive and enhanced greatly by the jog dial and decent screens - though the Karma is even better thanks to the larger buttons and bigger, higher-resolution display. The bundled Sennheiser headphones offer excellent sound quality, with both bass and treble being reproduced faithfully at high volumes.