We now nothing about the GS1000 yet, so I would wait.
The Cosmos S is not a case I recommend (here comes the fanboys...). To be perfectly honest, I totally despise this case, I got one with the side panel problems where they fall off and rattle. The cooling is not that great, my Antec 900 on low beats out the Cosmos S by 7-10 degrees system temp. All this I ignored, or modded so the side panels would STAY ON, because I loved the handles for going to LAN partied with my friends, until about a week ago. As I was carrying it something snapped, twisted the shape of the case, and popped my 8800 GT right out of the PCI bracket, and broke the cooler, luckily the card itself was fine. At first I thought it was the handle, but it wasn't it was the frame itself. The frame had snapped warping the case itself, and had popped my GPU right off the motherboard and bent it where it was connected to the case This made me quite angry, but Cooler Master came through and agreed to replace it for me. I will be giving the Cosmos S to my friend, I don't want it anymore. The Cosmos S is not a bad case, by no means, it's cooling is sufficient, it is extremely quiet, and it looks nice, but it lacks a lot of the quality I demand from Cooler Master, and all my computer cases.
On another note, I still recommend the Lian-Li PC-A70/A71. It is a great case with amazing cooling, is quiet, and is made with that legendary Lian-Li quality. The A71 is the A70 with a front door, so you do not have to have it.
http://www.silverpcs.com/product_info.php?products_id=487&osCsid=5b84ea088c395df06cc201c07cce3dd1
http://www.silverpcs.com/product_info.php?products_id=486&osCsid=a104c21a78cde7357a9677bcc91df972
Enjoy!