Rupes 15mm MK II vs. Chinese 15mm...my thoughts

I've tested just about all them
They all vary in torque and vibration
Only two that I've find to be smooth is the obvious Rupes and a brand name I own if youre in any of the FB groups I'm sure you seen them.

The thing is with the right pad weight, you can reduce or eliminate vibrations for just about any machine.
The issue then becomes can this pad hold up to a longthrow though, as not all are designed to take the abuse.

I got the pad weights/grams down to the Tee for what I sell and along with my Makita PO5000C and my old Griot 21 boss..

Whichever brand OP gets...make it the biggest throw.
More coverage, faster cut, swap to 5in plate for a tad more aggression. Stalls less

Majorty are 21mm , Mine goes up to 25

Makita PO5000C and allot of 8mm machines are smootheet with a 15g pad which is a LC thinpro

Longthrows vary pending brand, eccentric offset and BP(ie 21mm with 5in plate vs stock 6in)
Etc etc

Quality between allot of the china ones also vary , so do research

Alas, always use proper gauge extension which would be 12 gauge..or can go overkill and snag a 10gauge cord.
Wrong size will ruin even rupes machines