IMHO in engine, syn is good for the following:
(a) resists thermal breakdown better
(b) low temperature flow
The performance gap has narrowed significantly over the past 2 decades or so to the point where nowadays, conventional oils that passed ILSAC GF-4 or similar already comes neck and toe to those "so-called" syn in the engine lubricant performance. So, unless you have a seriously stroked engine that the sump cannot take on the extra heat produced by your engine, or you run your engine in -40C below all the time, otherwise, I personally do not see the true need to run syn (*or according to Mobil1/Castrol Syntec, they interpretation of "synthetic" in NA*).
Q.
p.s. if your car feels jerky, look into the engine's ignition or fuel problems first. Inferior fuel and/or poor ignition will cause that too.