I bought mine from solar.jean on eBay and it's been fine... but I've only had that one so I don't know any different. At least 90% of the time I use it on aluminium and I have used it with brass, mild steel and titanium perfectly well.
I've had no problems with the VFDs that came with them, other than an earthing problem which was my own fault.

Although it will be quieter than the Kress the cutting noise generally exceeds the noise from the actual spindle. There are much better reasons to get a water cooled spindle, such as rigidity and superior collets.

Quote Originally Posted by JAZZCNC View Post
a submersible water pump droped into darkened and sealed container with around 20ltr water
Same, except I didn't bother with the darkening and instead just recently added a bit of copper sulphate to the water. A gram is more than enough to stop anything growing in 20L of water.