The American Civil Liberties Union - a group indirectly linked to the Mexican government - has a nit with the Flake-Gutierrez amnesty [1]:

"Drafting comprehensive immigration reform is no easy task... [praise some provisions] ...Sadly, Title III of the bill attacks privacy by creating a national ID card. Creating a national ID card under the guise of a 'secured' Social Security card is not only financially and logistically daunting, it creates the possibility that we will become a society where 'your papers' will need to be presented at every turn. We urge Congress to strike this provision and build upon the hard work of Congressmen Gutierrez and Flake to keep constitutional problems out of this legislation."

Whether it will be struck - and if it is whether that will make the position of the bill's supporters weaker - remains to be seen.

For their part, the AFL-CIO says [2]:

AFL-CIO President John J. Sweeney says the approach to immigration in the 110th Congress "stands in stark contrast to the mean-spirited path that the House of Representatives took under Republican control in the last Congress." ...Milton Rosado, president of the Labor Council for Latin American Advancement (LCLAA), an AFL-CIO constituency group, welcomed the legislation...

However, they also indicate several problems they have with "guest" worker programs; the STRIVE Act contains one such program.

And:

"We have questions about the operational viability and the political viability of [the touchback provision]," said Frank Sharry, leader of the National Immigration Forum.

And [3]:

[The STRIVE Act] fails to protect the fundamental human rights of immigrants, refugees and asylum seekers in this country, according to the American Friends Service Committee (AFSC), a Quaker social justice organization... [it] offers little to address the root causes of undocumented migration and contains several troubling provisions... One such provision is "Touchback," which requires an applicant to leave the U.S. and re-enter the country to receive legal immigration status. This is not a practical starting point for the estimated 12 million undocumented immigrants now living in the U.S...

And, from this:

On the House side, Several Democratic freshmen campaigned against so-called amnesty to help their party win control of Congress... Among them was Rep. Nick Lampson, D-Texas, who won the conservative Republican district once held by former Majority Leader Tom DeLay... "He would not support a bill that has a road to legal residency for illegal and undocumented workers who are already here," said Lampson spokesman Bobby Zafarnia... Democrats also are facing opposition from unions. Many AFL-CIO member unions and the International Brotherhood of Teamsters are concerned that employers will choose to hire foreigners over more expensive American workers... They want limits on work visas for foreigners, but also full labor protections that would let them join unions... "The ideal immigration reform bill would not contain a guest worker program," said Yvette Pena Lopes, a Teamsters lobbyist. If one is created, the Teamsters and other unions want it to expire in three to five years, Lopes said.

4/5/07 UPDATE: John Sweeney of the AFL-CIO says:

...under the Bush plan, the 12 million undocumented workers in this nation will continue to labor in second-class status as newly defined "temporary" workers. This plan will only perpetuate the dire situation of these workers and their families, and will lower standards for all of America's workers. Our nation should instead provide a path to citizenship for these immigrants who are already working here, paying their taxes and enriching our communities. The key to raising standards for all workers is to ensure that all workers are able to enforce their rights. As long as there are workers who are unable to exercise their basic rights to the minimum wage, to a safe workplace, or to join a union, we will continue to have a second tier of workers... The theme of the Bush plan is inequality. It guarantees inequality now, for 12 million undocumented workers, and it guarantees inequality for those immigrants who come to our shores legally in the future. A two-tier society is not the America we want and is not the America that workers deserve.

[1] aclu.org/immigrants/gen/29177prs20070323.html
[2] blog.aflcio.org/2007/03/23/legislation-strives-for-real-immigration-reform/
[3] wfn.org/2007/03/msg00338.html