I have the bigger version of this machine
First thing i did was replace the controller (Parallel port) to the Mk2 controller of Andrej.
The stepper drives that come with this machine aren't verry good as well, i already had one of which the 5V supply failed.
They fitted a linear regulator that down converted the 24V directly into 5V. Those regulators are not designed to dissipate such voltage drops. So i replaced the regulator with a switching regulator. I'm planning on redesigning the whole control electronics into one integrated solution that contains 4 stepper drivers capable of handling 5A and the Mk2's PIC Controller.
There where some other small issues.
The cable chains where not big enough to fit all cables / hoses (i have a water cooled spindle) so i had to replace those as well
1 hose fitting of the spindle was broken when it arrived, and they seem like bad quality, to brittle!
There are also 2 plates of steel to cover the X axis ball bearing spindle, those where rusty. They should have at least painted those.
I use the machine to mill Aluminium on a regular basis, and it does a nice job.
One thing i noticed tho, is that you should not generate helical paths for holes. Helical paths use all 3 axis at the same time, and the power supply (10A) is not capable of generating enough current, so you miss some steps! which is off course devastating for the accuracy!
Another thing i noticed, is that when you move the Z axis down to Drill/Mill into the material, the entire X/Z axis assembly rotates around the x axis a bit. I feel that it is lacking rigidity on that side.
All things said and done, its still a decent machine for the price that you pay!