This case is clearly not of the 'quality' of the R3 Rainbow but it is far better designed. When building on a budget then that is actually more important. No USB3 but then the board I am fitting does not have that. It does have a rear RGB fan so I don't need to buy that. The side panel is only perspex but who cares at this price, it still looks good.
Building in it was better. The case design is very ridged due to two useful features. It has an integrated shroud over the PSU with a port so you can see the label. This means I can use a much cheaper non-modular PSU and hide the mess of cables. There is a wide gully up the far
side to run cables so no bulge in the side panel. This also helps case rigidity. It has far better HDD and SSD mounting. It seems 2x SSD and 2x HDD is no problem. It looks like it has radiator mounting but never used a radiator so don't know if that's good or not. There is plenty of room for a huge HD5970 GPU.
It does only take the 4 slot motherboards but this case is very suitable for a budget gaming system. (Gaming means good ventilation, room for a GPU and no CD ROM bay).
So although I prefer the look of the Rainbow R3 this CiT Beam is the intelligent choice for a very budget build.