60hz vs 100hz Refresh Rate (gaming)

good question.

maybe each 'motionplus' feature is different.
ya know, maybe one television will fix the problem and another one wont.

its all about frames per second.
the problem you have stated implies that you have a frame per second mismatch.. and when you turn on vsync, the frames per second are too low.

if i were you.. i would use fraps to see how many frames per second you have before and after turning on vsync.

you might be able to fix the problem by simply changing some software settings.

the easiest would be to cap the game at a specific frame per second.
if your tv does 60 frames per second.. that is an even number.
if the graphics card sends an odd number.. like 61 frames per second, you are going to start to see screen tearing.

all you need to do is one of two things:
1. determine if you need to use odd or even frames per second to stop the tearing, and then use either odd or even numbers as you go lower and lower until there are no more drops in frames per second.
2. buy a faster graphics card that doesnt dip to a low rate of frames per second.

you said turning on vsync fixes the problem but it feels sluggish.
that means there is a chance that the tv is displaying a solid 60 frames per second.. and not dipping down to 59-58-57-56-55 frames per second.