ITreviewed posted a review on the Sony VAIO P-Series Netbook

The machine features up to 4 hours of battery life with the included standard capacity battery and 8 hours with the 6-cell battery (sold separately for around 120). These are disappointing operating times considering you can get fully-fledged ultra-portable laptops with 12-inch and larger displays that run as long as this. Also worth noting is that adding the optional high-capacity battery increased the machine's weight to 708g. As you can see, the problem with the VAIO-P is that you don't get a lot for your money and the optional extras push an already expensive machine into the realm of stupid money. For a lot less financial outlay you can get a proper laptop that you can use to produce stuff on - videos, music, Web sites, blogs, novels, PowerPoint epics and other thrilling bits and bobs - rather than a small and not even affordable computer than you can use to browse the Web while you are out and about.

Sony VAIO P-Series Netbook reviewed