obviously they will be cheaper considerably. But my advice is don't buy if u can. And if u buy, do check very very thoroughly. For example, there r shops in HK who passes of refurnished units as 'brand new parallel import' units.
Manual and power adapters being diff are minor issues but if the unit fails n u need repair services, u might run into issues.
For example, Panasonic SG charges extra for repair jobs if u send in a parallel import unit. Heard its 1.5times but this is what I heard.
what brand r u looking at? Check out the brand's policies with handling such sets. Though camera sets generally don't fail, but its simply your own onus if u get a parallel import one and it fails.