According to a Blaze study
The devices used for testing include a Nexus One running Android 2.3 and an iPhone 4 with, presumably, iOS 4.3. Both operating systems sport WebKit-based browsers.
On average, Android came in 52 percent faster with an average page load time of 2.144 second versus 3.254 seconds for the iPhone. Android apparently outperformed Apple’s handset on 84 of the tested websites, including those that are not optimized for mobile access. On mobile sites, however, Android’s lead dropped to just three percent.
Regarding that Nitro issue, a follow-up note on Blaze’s site says the following: