Via TaxProf, you can download a Congressional Research Service report Economic Issues Surrounding the Estate and Gift Tax: A Brief Summary, by Jane G. Gravelle. The report is short and summarizes the arguments, pro and con, with respect to the repeal of the estate tax. It makes several points that are worth emphasizing:
First, the estate tax adds progressivity to the tax system.
Second, "as is also the case for the income tax, neither economic theory nor empirical evidence clearly indicate that the estate tax reduces savings." (Emphasis added.)
Third, at worst, there is only a minimal negative impact on small businesses and farms.