bit-tech published a review of Shuttle's SP35P2 Pro XPC
A quote from the article:
Shuttle SP35P2 Pro XPC Review
While it's obviously a very capable gaming system, it does get quite noisy when everything is hot and loaded. With headphones on or your speakers turned up this isn't a huge problem; but with it sitting on the desk next to you, it becomes far more obvious than a case sitting under your desk.
You could build an alternative system like an Abit IP35 Pro, an Antec P182 and a Corsair HX520 power supply for about £250, give or take a few pounds. Personal choice will vary the components, but in comparison the Shuttle SP35P2 is £293 -- that's £50 more, but the space saving and attention to detail in the design, as well as the integration of the SP35P2's parts is second to none.
On the other hand, many people keep their cases between upgrades and sometimes even their PSUs too -- so as a whole purchase, the Shuttle XPC concept gets less inviting. Unless, of course, you're specifically looking for a small form factor with desktop level performance and don't want to be constrained by the inability of a notebook's expansion -- then the SP35P2 should be ideal.
Most of the people I know have had at least one Shuttle XPC at some point. We've all tried it, but it's an ideal that all of us grew out of and went back to ATX. My current case is a massive Antec P190, but does the SP35P2 make me pine for that small world after all? No, but it does a great job in trying -- it looks fantastic, its build quality is superb and it's got an unmatched performance-to-size ratio.
Even though Shuttle has tried to maximise the SP35P2s flexibility as well, I feel this SFF is stuck in a no man's land between a completely portable notebook and a vastly more extensive and easily upgradeable ATX PC. If you're a LAN gaming nut, then the SP35P2 is a must buy... unless you have a car. Or perhaps the missus just wants one because she thinks they're cute? There's dozens of reasons why it's a good idea, but also a dozen reasons why it's not -- the SP35P2 Pro still hasn't made the XPC a definitive buy.
Shuttle SP35P2 Pro XPC Review