Up to her as I don't feel jerky flippers on any of those models. 4s likes to go all the way thru broad powerband. 2s much more peaky engine but maybe what she really means is 4s engine braking & uneven off & on gas may be jerking her around. 2s coast better although new 4s are reducing engine braking.
Whitedust, again you post about sleds you know nothing about! Have you even sat on either one of these sleds let alone ridden them?? You post on every thread about sleds, and you bash every 2s thread on here.
To the OP; Whitdust is a 4s nazi, if its not a 4s its no good in his opinion. So just take his opinion and throw it out the door.
I have logged real world miles(not internet miles) on a 600 etec. It is a very healthy motor. But it is far from "peaky or neck snapping" It is IMO a very mellow motor at anything under WOT. At WOT it will get up and go, but it wont pull your arms out of the socket.
I have not ridden a 1200 Doo, so I cannot give you any "real world comparisons".