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I have bought USB hubs from different shops. If the brands of the hubs are not popular or well-known, the quality may not be good enough.
1. The conductivity of the cables may not be high enough to drive bus-powered hard disks
2. The hub could not be powered externally.
3. In some cases, the hub could be like the one I bought from Taobao:
Fig. "Hi, I am a USB 2.0 Hi-speed Hub!"
Fig. "Ha, I have no 'heart'!"
The above hub does not have any hub controller IC. With connecting all D- and D+, the only use is to share power... Oh no!
So, to avoid buying bad quality hubs, we could design and make our own ones!
This is an Altium PCB project for a USB2.0 Hi-speed hub. What not USB3.0? The reason is that the controller and sockets are much more expensive than 2.0, and for daily use, USB2.0 is fast enough 
For saving cost and reduced size, GL520G with SSOP28 package has been chosen.
However, some functions like Individual power mode and even power enable function are NOT available in this package.
If we are going to design a more advanced hub, GL850G in LQFP48 would be a better choice.
Fig. The schematic of the GL850G USB Hub
The PCB was a 2-layer board which was drawn in a semi-circular shape...
Fig. The Hub's PCB layout
 
Fig. The completed product with the GL850G hub controller
Fig. Using ChipGenius, the information of the controller could be obtained
There were several special features:
1. Can be powered externally by 5V power supply (5.5x2.1 Connector)
2. All solid state capacitors
3. LED indicator (power and standby)
4. Over-current protection (by PTCC)
3D printer was used to print out a plastic casing for the hub.
(For testing, a very thin casing, only one layer, was made)
 
Fig. With 3D printer printed casing
External supply was needed when plugging in some high-current devices (like charging cellphones and hard disks) to the hub.
Fig. A 5V 2A power supply with 5.5x2.1 Jack
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