The inaugural issue of PATHWAYS, a new magazine on poverty, inequality, and social policy, has articles by the three Democratic candidates on the their anti-poverty proposals, along with an evaluation by Rebecca Blank, who's probably the top economist specializing in welfare issues (she was on Clinton's Council of Economic Advisors for a time and is currently a professor at the University of Michigan). Here's the PDF of the whole issue. It also has some great other material, including an update on inequality from Emmanuel Saez.
Overall, Blank says that all three say good things. As with most issues, the policy differences between the three candidates are slim. Here's the heart of her review:
Clinton, Edwards, and Obama each propose multiple policies,
many of which are worth considering, but it is hard to tell how
they would prioritize their current list of proposals. Presidents
face limited resources and hard choices once they actually
enter the White House and have to decide where to place their
political chips ....
Obama, Edwards, and Clinton all have multifaceted and serious
anti-poverty plans. Anyone concerned with poverty issues could
happily vote for any of them. Edwards has made poverty a cen-
terpiece issue for his campaign from the beginning; Clinton has
the best early childhood proposals; Obama is the most thought-
ful on jobs for disadvantaged youth and urban change and (for
my money) the most creative in putting new policy ideas on the
table, such as low-cost Internet service in poor neighborhoods.
But all of them understand that the measure of this country is
not just the size of its GDP or the wealth of its richest citizens.
America must also be measured by how we assist those who are
our poorest citizens, making sure that they have the opportunity
to find a job, to support their families, to educate their children,
and to catch onto the American dream.