Sadly, the U4 is merely competent when it comes to actual sound quality. Listen through the supplied earbuds and it's clear that you're not listening to a top-end player; there's a stronger bass than you might normally hope for and clarity isn't bad, but the tone is slightly insubstantial and you soon notice that the little details you normally listen for in a song are subdued or missing. Firing up Stronger from Kanye West's Graduation, the sound is certainly punchy but the bass drums thud through the track without the lively bounce you can hear on a better player.
Meanwhile, the thick guitars in the chorus of Velvet Revolver's Can't Get it Out of My Head sound messy, tinny and over-distorted where they should be rich and beefy. The U4 doesn't do well when it comes to more sophisticated material, either. Milonga en Re from Gidon Kremer's Homage to Astor Piazolla can sound sublime, with the forlorn solo violin rising and falling over a backdrop of slow, understated tango. Through the U4, however, it never quite comes to life. The little player can't quite manage to resolve the different instruments or give the violin the aching sound it needs.
Still, when a player doesn't sound great through the bundled earbuds - and let's face it, most don't - I usually hold out hope that things will be different when I plug in my reference Denons. Well, the U4 show signs of improvement, but there's still something missing.
There's power at the bass end and some reasonable definition at the top, but little in the way of warmth, while the player still struggles with more complex or thickly-layered arrangements. Sooner or Later from N.E.R.D's Seeing Sounds is a great example of Pharell William's expert layering of percussion, keyboards, rock guitars and thick, harmonised vocals (even if it does go on for far too long) but the U4 doesn't quite do it justice. Again, the sound isn't actually bad at all, but you're missing out on the sort of texture and detail that makes a great song sound really brilliant.
Let's be clear: at this kind of price we don't expect miracles and you could do much, much worse than the U4. All the same, with the Sansa Clip and Creative Zen Stone series around, you could also do a little better.
With this in mind, the Clip retains its place as our king of the miniature MP3 market. It's a shame, because the U4 has - to my mind - a much more attractive design and a nicer overall feel, and would - I think - do an even better job of persuading anyone you gave it to for Christmas that you had lavished cash on them when in fact you'd been quite tight (or maybe just credit crunch-conscious). With this in mind it's still a good present for anyone you know who values style over sound quality, particularly as the output is more OK than awful. If you're planning on buying one for yourself, however, I'd still push my money SanDisk's way.
A nicely designed budget player that does a great impression of something more expensive. However, sound quality is mediocre in comparison to the SanDisk and Creative alternatives.