It's something of a testament to the NP2900 that sound enhancement effects aren't needed. The sound produced is notably better than that of the AirStream10 - which you'd hope to be the case given the extra speakers - and a commendable match for the Squeezebox Boom. Sticking on the plus side, that holds true no matter what you throw at the NP2900 - whether that be The All-American Rejects, the London Philharmonic Orchestra, or the X-ecutioners.
There's an impressive level of clarity to the acoustic brilliance of Mona Lisa from The All-American Reject's When The World Comes Down, also highlighted in the vocals of The Pierce's Catherine and Allison Pierce in Another Heart Calls from that same album. There's no lack of punch in heavier tracks such as Real World though.
Venturing into the slightly more complex realms of Muse's latest opus, The Resistance, and the beautifully complex Exogenesis - all three movements of it (calling them tracks is something of a disservice) - I was impressed with how well the NP2900 coped. The narrow soundstage doesn't quite do Matt Bellamy's work justice, and on this piece in particular turning on LivingSound did more harm than good so there was no assistance to be had there. Nonetheless, for such a relatively small system the reproduction was still commendable. The less musically adventurous, but still utterly listenable, Unnatural Selection fared much better, with plenty of presence and a less 'muddy' sound than the AirStream10 which, in fact, the NP2900 bested with every track I could think of throwing at the two systems.
Considering the two are priced within a hair's breadth of each other the choice between the two pretty much hangs on whether FM and DAB radio are at all important to you. Or, I suppose, if you are particularly enamoured with the AirStream10's arguably superior styling.
The NP2900 can't best the Squeezebox Boom in the performance stakes, but it doesn't lag too far behind either. As a result, the choice between the two is pretty academic - I do think the NP2900 looks better, though.
The Philips Streamium NP2900 might not stand out particularly, but luckily its performance means it doesn't need to. Adding a radio tuner to the mix wouldn't have done the system any harm, but the omission shouldn't be considered a death knell by any means.