3D PLASMA / LED vs 3D PROJECTOR ?

There should be no difference, no matter the display. 3D effect and depth is determined by the source material.

Most, if not all, LCDs and plasmas suffer from crosstalk or "ghosting" however, where the image from one eye leaks to the other eye because of pixel speeds in the display being too slow. Ghosting varies by model and manufacturer.

If you get a DLP projector or a DLP 3DTV, you won't have the problem, as DLPs do not exhibit ghosting, and it would only be an issue if you had defective glasses.

The larger the screen, the more 3D impact you get. Any 3D projector will give a more impressive 3D experience than any plasma, because plasma's aren't big enough. Sure, plasmas have better contrast and all, but for 3D, size trumps contrast.

Among 3D projectors, LCD, LCOS, and DLP have their advantages and tradeoffs. You will fine strong advocates for each technology here.