The SG33G5 Pro is nice but it's not revolutionary or anything like that. The bottom line is it's the same XPC from three years ago with a slightly different exterior design and a new motherboard installed. The biggest problem is working out where exactly this particular XPC fits into the market, not just as a whole but also as far as Shuttle's line-up goes.
Prior to testing the unit for video card performance I was using the SG33G5 Pro as my own little home theatre PC in my bedroom hooked up to a Samsung 32" LCD TV. It was a very capable HTPC but when you price it up it's not that cheap, you then throw in the fact that the odd shape means that it might not always fit into your cabinet. It doesn't feature an IR port or anything fancy like that so if you don't want cables running around you need to get a wireless keyboard/mouse. The fact that it didn't have a PS/2 port was a bit of a pain as well as I had to grab the more expensive Logitech G15 USB keyboard to use it.
The other end of the stick is a gaming PC and the single slot design really prevents it from being anything too serious. Sure if you're a casual gamer and use a maximum res of 1280 x 1024 you would be fine but if you wanted a nice little PC that lets you game on that 24" monitor you're going to run into troubles.
As a gamer you might find yourself venturing into overclocking and the SG33G5 Pro didn't have any trouble getting our E6600 to 3GHz; the problem is though that we're not limited by our processor, we can easily stick in a E6850 and have 3GHz Dual Core with a 1333MHz FSB, the problem is the video card. All the CPU power in the world isn't going to let you game at 1920 x 1200.
There is of course your general office PC/workstation but the cost of one means that it's out of reach for most people. The work horse PC isn't really about looks but more about functionality and costs, while this does the first fine the latter isn't done so well.
You're not going to have any dramas getting a hold of one and as for value for money compared to other XPCs it's pretty good, unfortunately with a little bit of work you could build yourself something better performance wise for the same cost. $500 AUD gets you a pretty good case/power supply and motherboard these days, and generally a lot more expansion too.
The SG33G5 Pro is a good quality product, though there are cheaper ways to get a small form factor PC up and running, Shuttle really need to revolutionize SFF computing again like when they first entered the market, how they can do this? Well no one really knows - otherwise it would've been done.