Read this blog on Ecommerce site search vs google custom search for more information.
In any eCommerce website, there is no one tool that is more important than the search bar that helps in sales. The real truth is that many eCommerce websites have been trying to get the secret sauce that drives great search experiences on Google. But hardly few eCommerce websites (including Amazon) have been able to get their search to Google’s level. Statistics have shown a high correlation between people who search and people who buy. This gives a great reason to optimize your eCommerce search engine. To be concise, the search bar is the eye of an eCommerce website.
Custom Search Engine is an ad-supported product that provides similar capabilities to GSS, including the ability to build custom search engines for sites or pages, an image search for your website, and customize the look and feel of search results.
Google CSE offers different plans for different business needs as well as lots of customization tools. Being supported by ads, there is a good chance that it will end up showing the ads of even your competitors on your website. Its design limitations, ads, lack of speed made many of former Google search products’ customers look for a better solution.
Google Custom Search allows users to add a search to their website quickly without any coding. Google custom search engine uses the regular Google index of your website and uses it to deliver the search results. While the results are decent, you will not be able to meddle with the ranking algorithm or control the indexing of data. We will later address two ways to create a custom search engine, one being Google CSE and the other, ExpertRec, an alternative. In creating your own Google Custom Search Engine you can prioritize or restrict search results based on specific Web sites and pages you specify. Once you’ve defined your search engine, Google provides code for a search box that users can copy and then paste right into their own Web site or blog.
This doesn’t do particularly good if you are running an e-commerce website as GCS does not support indexing a product feed directly. Also, having your competitors ads running on your website can damage your conversions. If you have a product feed, you can create your own eCommerce search engine in 5 minutes from here.