The performance is much better. It is waaaaaaay more rigid than the Sherline, the frame being 6" by 5" solid aluminum for both base and column. No backlash (.0001" on all axis, measured with a .0001" test indicator) and much, much faster. Jogging at 120IPM no sweat. I turned it down to 100IPM because much faster than that was kind of scary.
The perpendicularity was mainly achieved by gluing shims to the end of the block of the right thickness in the right places and testing this with the block stood up on the surface plate with a square. Then the JB weld was used. After that I did some checking and a little draw filing to get it square within .0015" over 5". Most of the sanding was done to get stuff flat.
I don't like the look of those Chinese spindles for several reasons. First, they are a bazillion RPM, min RPM is too fast. Second, it is a cartridge type spindle and would require a precisely bored hole in a mounting block, something I can't do at home. Third, ER nose. I can't preset my tools in a multiple tool program. And fourth, it's Chinese made. The Sherline spindle is of much better quality.