Your spindles seem much smaller than larger CNC Routers’ 2.5Kv spindles, how can they do the job as well?

The spindle is proportional to the size of the CNC.  A STEPCRAFT CNC with a 800W spindle will be able to do the same jobs as a large 4×8 foot machine with a 2.5Kv spindle, however, it will not be able to run as aggressively.  So If you can run 60 mm/sec on a large industrial machine with a more powerful spindle, you can do the same job on a STEPCRAFT with an 800W spindle but you might only be able to run at 30 mm/sec.   You will also have to take less material off per pass on the smaller machine than you can on the larger machine.

You also need to keep in mind that a good quality 2.5Kv water-cooled spindle can cost more than entire STEPCRAFT CNC system.  It is really apples and oranges. If you are in the market for a machine for industrial or high production use, then you should be looking at a larger CNC with a more powerful spindle.  However, if you are looking for a precision CNC that can do just about anything, but you would need to run less aggressively, then the STEPCRAFT would be more than enough machine.