Part of it is the motors, part of it is how they are mounted. My SVP with these motors was fairly quiet in RA but noisy in Dec, with the Dec motor being mounted directly to the saddle, allowing vibration to radiate into the OTA with not a lot of damping before it gets there. The non-H EQ5 will also have this issue.
Another thing, the CG-5 trick of slewing manually at a slower speed to get quieter operation doesn't really work for these stepper motors, they are very close to the same loudness at any of the slewing speeds from 6-10 I found. And of course the loudness lasts longer at speeds less than 10.
My opinion is the OP should not consider anything other than HEQ*/Atlas/Sirius if they are concerned about noise.
It's servo motors vs. stepper motors. Former are much louder esp. mounted in a plastic bass reflex speaker enclosure.