230v or 120v motors

I was talking to a electrician about commerical equipment in general. He says the equipment made to run 230v like some of the portable extractors options, should use smaller vacuum motors compare to 120v machines? Also goes on the saying 230v equipment should be weight lighter and use less ampage draw?

In this industry, do manufactures rate the surge draw or idle draw of it motors? Lets take an example like the ninja500. Uses two 120v corded with 15amp draw. This it mean i'm using 7.5 amperes after start-up but using 15amp at the intial flick of the switch?