Magento is a very complete solution in order to have a big shop, with more than 500 products.
But, for newbies, it's very difficult to load and modify it.
Today, I have a website on magento with more than 20,000 products, and we still have issues.
It very difficult to configure it, and without a nice optimization, you will have very slowly website.
I advise you less than 300 products to use prestashop.
