My friend has this case and I must say that it is a very nice case. The power supply is adequate for most set ups, unless you're getting an x1900xtx in crossfire or doing any SLI stuff. It is quite a quiet case, and for the price, it's a good deal. I on the other hand, have the Antec P180B, which is more expensive, and doesn't come with a power supply, but is much much better than the sonata II, albeit quite a bit larger. It comes with 3 fans installed, and space for a few more. All the walls, and even the front door, are made to be silent, it has 3 layers of... well stuff, to make it quiet. The P180B doesn't have the piano finish that the Sonata II has, but it does look very elegant. It has a sturdy front door, and has a separate chamber for the PSU and one of the drive bays, where it's basically a wind tunnel. You can take out the bottom drive bay, which is in the wind tunnel thingy, and put in a water cooling heatercore if you'd like. I must say that the removable drive bays are really nice. They've all got the little silicone pads on them to reduce vibration noise, and they slide in and out quite easily. The top one has a little compartment box on the back where you can put screws, twist ties, your spare key, weed or whatever else you want to in there. The one thing you'll want to watch out for in this case is to make sure the power supply cables are long enough.
I can still say that getting the sonata II is a good deal, I just like my p180b more, possibly because it's mine. It's a bit of a pain to bring to lan parties though, the sonata II is a heluva lot easier, though the fact that my friend has a 21 inch monitor makes up for that fact, lol.
Just a side note, you will spend a lot of time polishing your sonata if you chose to get it.