As well as looking fantastic the Philips SHE9850's also sound very good. Both Riyad and I were amazed with their performance and agreed that they really are a testament to just what is possible with a single driver. Of course that's a verse Shure has been preaching for over a year with the now £110 SE310's, so let's compare the two.
A play through Muse's Dead Star/In Your World EP (their best work if you ask me) was a real pleasure, with excellent high-end and mid-range clarity, coupled with a controlled level of refined bass. That said, the SE310's picked out a little more detail from the Apple Lossless files I was feeding them, but then the SHE9850's produced a fuller, more rounded rendition.
Turning to My Chemical Romance's The Black Parade the story was the same. The SE310's, again, offered a more accurate reproduction, making the intense guitar riffs more penetrative while also singling out the vocals on tracks such as This Is How I Disappear. However, the SHE9850's redeemed themselves once more by balancing slightly less (comparative) precision with an overall larger soundstage and, to me at least, that gave a better sense of depth and immersion in the tracks.
Out of curiosity, I also compared the single driver SHE9850's to a pair of SE420's and it was clear that the dual-driver solution was better, but the difference was nowhere near as profound as I expected. It's probably also worth noting that with my iPhone set to the same output volume, the SHE9850's were decidedly louder (have a lower impedance) than the Shure SE310's. That's by no means a deciding factor for many, but if your MP3 player suffers from a low-power output it might just swing things in Philips' favour.
As Riyad observed when he compared the Shure SE420's and the Klipsch Custom-3's, if you leave pricing out of the equation then the choice is all about how you prefer to listen to your music. Shure, with the SE310's, has the edge when it comes to absolute clarity while Philips presents a less technically accurate but at the same time warmer sound. If I had to make a call, though, I'd opt for the Philips SHE9850's. Factor in the £40 price difference, arguably better design and package and it's a clear win for Philips.