Reports suggest that the deal between as-Sistani and as-Sadr is holding.
In the short run, lives and property may have been saved, and given Iraqi sovereignty, US forces had no choice but to wait out the negotiations.
Whether leaving as-Sadr free to try some other maneusver later, at some time opportune for him, and avoiding a punishing confrontation serves the interests of the Allawi government and the US, even time may not tell.
The Shi'a can afford to wait out the elections. They are the majority. Fallujah, meanwhile, remains an abscess on the iraqi body politic, and the Ba'athists and Islamists there run the risk of being marginalized in an election. Expect more trouble from that quarter.