The processor is same with your 1st choice, but this one doesn't has dedicated VGA, thus more cheaper. If you don't have a plan to do a lot of medium range gaming with the notebook, then you can pick this one, else pick the 1st choice above (samsung).
I would say hands down the first one is the best bang for the buck More ram bigger hdd better CPU. I also think the graffix card is better then the other two and if not better then the second one its just as good. The last one does not even compare in my eyes the specs are way below for the price.