For what you are doing doubt you'll notice a difference between the 2, but the i3 are usually better (would need the models to make sure). Get the cheapest and toss in a SSD that's where you will see the biggest difference in what you want to do.
In terms of overall performance, AMD quad core mobile CPU are considered to be equal to or have lower performance compared to a current generation dual core Intel Core i3 CPU. It depends on which AMD you are referring to because there are two different "families"; Beema are low end APUs for entry level laptops and low power consumption. Kaveri are mainstream APUs that are more powerful than Beema APUs and are considered to be roughly equal to the Intel Core i3 CPUs.
Intel CPUs consume less power which in turn provides better battery life.