Magento eCommere has become quiet popular not only for its vast number of features BUT for the fact that it is customizable unlike shopify, volusion or Bigcommerce
When you are putting your money into somebody’s hand then you need to know how much ownership of the application you can take, in case of hosted applications like shopify, volusion or bigcommerce that is not possible the moment you stop paying them the monthly fee you will NO longer be able to access your website, so it is over!
With magento customization is one big asset PLUS the total ownership is another, of course it doesn’t give you the gurantee that if a website is built on magento or wordpress your sales will rock, matter of fact even shopify can’t give you that guarantee!
Unless you take measures to promote your products your website will not get the traffic, irrespective of the application you may have used. Much depends on organic SEO, I prefer that more than google adwords as it is retainer and the efforts you put on it remain for much longer time period.
Think wise before investing your hard earned money.