Which Ecommerce platform is best

I have a client and they want to build new ecommerce store so which platform i suggest him. Simple functionality.

Magento, X-cart, Zen cart, oscommerce?

Magento is best if you are good in PHP.
Otherwise use OpenCart

I prefer Magento. Easy to use and highly compatible on Libux which I use.

thank you all for choosing me a best ecommerce platform.