A few pictures of the new Shuttle range here:
http://forums.overclockers.co.uk/showthread.php?t=18230635
The SH55J2 for around £160 is not too bad for the money as even a socket 1156 H55 mini ITX motherboard is around £80 and a similar 1U PSU around £40. The new cases can work with a mini ITX motherboard and you can use the 500W PSU from the H7 and J3 series too.
OTH,expect the same quirks you get with Shuttle SFF PCs such as being picky with RAM.
Also,the new cases are mostly steel too.
I would definitely have a look on the SFFTech forums and see any user comments on the system.
The SG07 is also worth having a look at too:
http://www.overclockers.co.uk/showproduct.php?prodid=CA-071-SV
Sometimes you can get it for under £130 on offer if you look around. It is not much bigger than a P2 Shuttle in size and it seems to have decent cooling although the case could look nicer IMHO.
You could then get a socket 1155 motherboard with one of the new Core i3 processors being launched in a few weeks.
The socket 1155 Core i5 and Core i7 processors also consume less power and run cooler than the socket 1156 Core i5 and Core i7.
The Lian Li PC-Q08 is also a nice case and has good reviews. However,it is a taller case than the SG07 and SH55J2.