Is there a large difference in image quality?

Search around a bit. This has been discussed ad nauseum.

There are many advantages of a bigger sensor: potentially larger pixel count, better optics availability and better (shallower) depth of field.

Okay, thanks.

I am just looking at a camera... it is either 2/3 inch or 1/2 and it is 9k USD new.

Forget the name... I think a Sony.

EDIT: Don't want to doulbe-post so here: it is the Panasonic AJ-SDC615.