The Cooltek Coolcube has two stories to tell. It is, on one hand, extremely compact with its dimensions of 200 x 210 x 240 mm and can hold two hard drives while easily taking a GeForce 650 or 660 graphics card, thanks to the two slots and 185 mm of space, but it lacks a 5.25" slot, and the power and I/O implementation is quite basic in terms of engineering. Its strongest competitor is clearly the PC-Q7 by Lian Li: It is slightly larger, offers a few extra colors, the external drive bay, and better internal engineering for slightly less, but lacks audio I/O and dual slots. So while they are similar in size, Cooltek's approach is clearly geared towards creating the utmost space available for hardware, while Lian Li tries to offer as many drive bays as possible at the cost of expandability.
I do believe Cooltek has chosen the superior approach with a better set of I/O and the ability to install a midrange graphics card into a compact case. Both are things people should value enough to spend an additional five euro. Cooltek just needs to add a couple color options and a better engineered I/O and power button to make this case perfect!