I just read a newspaper article saying that the Nexus One sales have been disappointing so far, with only 20,000 sold in the first week. This figure is compared to the 1.6 million iPhone 3GSes sold in June.
I'll admit to a bias against Apple, but even allowing for that I don't think the comparison is fair. Apple's new phone was going to an established market with a loyal customer base. Google is trying to sell into a market that Apple dominates and has largely saturated already. From that perspective, sales of 20K are very respectable, especially when you compare the coverage that the iPhone enjoys from AT&T versus what the Nexus One has from TMobile.
Depending on how serious Google is about Nexus One, they can overcome their late start. That is demonstrated in the history of just about Microsoft product. Still, even if Google has launched Nexus One purely as a strategic threat to force concessions from Apple, the sales figures show that they have a ways to go before this threat is credible. They've launched Nexus One, but now they need to do something more to demonstrate that they're serious.