Square Box AV
A brief tot up of the component prices of your first PC (with some filling on of blanks), and it comes in at around £240. The bottom option, not surprisingly, comes in at about £15 more.
They're both reasonable specs for the money, assuming you're not being quoted too much in excess of the prices I've given. My personal choice (without knowing more about the companies selling the PCs and prices charged) would be the AMD PC.