I would go with the Sony

Definitely the Sony Vaio. Or the Acer Aspire One AO756-2868. Only buy the Dell if you are desperate enough to buy a cheap, crappy, 5-year-old laptop.

The AMD processor in that Sony is worthless, when you buy a laptop you can skimp on storage space and RAM because they are really easy to upgrade, the processor and motherboard are not. You want something with a solid processor and that is built with cooling in mind. Those Sony's are hard to take apart and expensive to fix, that being said Acer and Dell are both worthless.

Really the only brands I trust are Asus and Lenovo (IBM), If you want something fast and pretty go with the Asus http://www.newegg.com/Product/Product.aspx?Item=N82E16834230706, if you just need a laptop that will last a long time go with the Lenovo http://www.newegg.com/Product/Product.aspx?Item=N82E16834246488. If the only options you want to look at are the computers you provided in your post, then yes the Sony is your best choice.

I was an IT professional for 4 years. If you like I can provide references : P.

Its 2 small screws on the back panel to upgrade RAM or storage, even if you don't want to do it, someone will do it for cheep. I do that kind of stuff free for friends. But you have to take the whole thing apart and reassemble it to upgrade the processor, or change the motherboard.

Lenovo G570 (4334EGU), and ASUS VivoBook X202E-DH31T. If you don't want to spend more than 400, look for refurbished versions of something in those brands.

or if you don't like those brands, you can look for something with an Intel core 2 duo or I (i) series processor or something over 2GHz and that is at least 2 cores. And at least 4 Gigs of RAM but you don't need any more than that.

Alright, small and light, whats your budget? 400-600? I'll Find something for you.

Small and light is expensive :/ the closest to your price range I could find is this one "lenovo IdeaPad S400 (59342932)" at 499.99 can be found at www.newegg.com/Product/Product.aspx?Item=N82E16834310635.

If you can put up with a normal size laptop "ASUS X53 Series X53E-RH31" can be found at http://www.newegg.com/Product/Product.aspx?Item=N82E16834230571 for 339.99.

I recently got an Acer Aspire 5749Z-4706. It's pretty respectable for a cheap laptop. My only real complaint so far is that they didn't make any cuts in the chassis for anything except the battery. So, if you want to upgrade/change out the hard drive, memory or any other component, you have to unscrew the entire bottom cover. If you can live with that and the large screen, it's not bad. The price seems to have gone up a bit since I got mine, but there are bound to be more sales. http://www.buy.com/prod/acer-aspire-as5749z-b964g50mikk-15-6-led-notebook-intel-pentium-b960-2/227013323.html