A recent article on Ars Technica suggests that the Intel 45nm low-power Silverthorne CPU (as used in the Menlow platform) "will be clock-for-clock slower and less efficient than a comparable ARM part, especially on integer-intensive Web and productivity apps".

In order to be performance competive with ARM, Intel clock speeds may have to approach 1Ghz level or higher which will probably increase power requirements resulting in quite heavy devices if a 6 hour lifetime is going to be realistic.

Obviously this is just speculation, but it will be interesting to see how the real devices perform and what they look like - the form factor may be much larger than what we are used to with Nokia devices which could be a deal breaker for some people. And to match a Nokia form factor, the devices may not run for anything like as long. Or Intel could pull a rabbit out of the hat and beat Nokia/ARM every which way.