Given all of its features, I almost don't care about how the JB7 performs - it's that good at what it does elsewhere. But to complete the picture, I can report that it's a very capable little player. In fact, given all the electronics and amplifier built into such a small box, it's surprisingly good.
I wouldn't go so far as to call it outstanding, though. I hooked up a pair of Sonus Faber Concertino speakers to the spring clips, played the Killers' excellent album Sam's Town through it, and though the JB7 picked out all the detail in the complex tracks, it lacked a little dynamic range - there wasn't quite as much punch to the music as I'd like. The same applies to the bass output: shove a bit of Jamiroquai through it and the normal squidgy bottom-end fails to come through with as much control as it could.
But that's probably just me being picky. After a few hours of listening, I hardly cared about that at all - there's plenty of volume and the Brennan never gets too muddled whether you hit it with complex classical, such as Mahler's 6th Symphony, Metallica's classic 'black' album or Ulf Wakenius' cool Swedish electric guitar-based jazz. The Brennan manages to sound crystal clear and unstrained throughout. As I said earlier, despite the niggles, this is remarkable in such a tiny all-in-one box, and it's worth sacrificing a little storage for quality: the JB7 loses some of its musical depth when you rip at 128Kbit/sec, so it's a good idea to rip at higher bitrates.
As a compact, stylish digital music system, the Brennan JB7 is hard to beat, but it offers so much more than that: USB input, backup and file transfer, recording from external sources and CD ripping that really couldn't get any easier.
There are niggles, of course, such as the horrid remote, and sound quality could be better for the cash, but these are small in the face of what is a highly successful overall package. If you're in the market for a decent iPod music system, you might want to consider one of these instead.