Pros: Dynamic, detailed, extended, musical.
Cons: Not the last word in comestics, if one is worried about this.
Not easy for me to describe as I'm not used to audiophile terms. But I hope this help anyway.
This is such an interesting DAC, with its ultra powerful power supply, a Blue Circle tradition. Starting from this point, one should know that its presentation is extremely dynamic. But, at the same time, it's also considerably delicate. Music comes with very good body, air volume. Strong and speedy bass. Very clear and detailed mids and highs. Besides all one can hear on mid frequencies, from guitar strings to piano keys, it's very, very important that it goes really deep on high frequencies; there's no sounds cuts. And it does that with crystal clarity. Am I clear on this? I mean: this is real high fidelity. But absolutely nothing to worry about: this DAC is anything but listening fatiguing. In fact, it's very natural. And natural is musical. Lots and lots and lots of soul and emotion. I've been simply delighted. No less. Compared, for example, to Cambridge Audio DACMagic (the first one), the british DAC stays way way behind in terms of dynamic, air volume, high frequency extension and especially soul and emotion. DACMagic used (and still does, no?) to be considered a high value DAC. But, imo, it's far behind BC507's general quality. Right one pays way lot more for the Blue Circle unit. But what I'm saying is that BC507's price reflects perfectly its overall performance. Unfortunately I did not have the opportunity to compare it to higher priced DACs but have no doubts it would go very well.
It seems very well made, quality utilitarian chassis. Not beautiful for the ones who values comestics aspects; its appearance will not impress your brother-in-law.