Either way, the Resolution would do nothing to stop the NSA program (or bring it into conformity with the law), or to check the Executive power-grab, and would likely only exacerbate the problem. Indeed, even if, by some miracle, the Resolution were to win a majority in the Senate, it still wouldn't accomplish anything, because Cheney and company would respond: "Thanks very much, but we respectfully disagree and will continue business as usual."
Thus, I'm afraid that from the perspective of the future of the balance of constitutional powers, the Feingold Resolution could not improve things any, and might, if defeated, actually set Congress back even further. On the other hand, the Resolution does keep the issue in the public eye, and, frankly, at some point those who are concerned about the President's aggrandizement must do something to assert constitutional principles. In the absence of any other possible congressional options for dealing with the problem, it might well be worth the practical risks.
So, ultimately, I'm fairly agnostic on the tactical wisdom of the Feingold Resolution. But whether or not that Resolution remains viable, I think the efforts of those concerned about the Executive's power-grab -- e.g., Senators Feingold and Specter, among others -- would do well to put their energies to work in support of the Schumer bill. It's not an either/or choice.