One of the biggest things to get your head around choosing an e-commerce platform is the different between 'hosted' and 'self hosted'.
Disclaimer: Although we are a Shopify Experts, this post is impartial.
A self-hosted e-commerce solution is hosted on servers that you procure through a provider such as Rackspace. It means that you (or your web agency) need to source, set up and managing the hardware infrastructure and operating system that your e-commerce website runs on.
A hosted or 'managed' e-commerce solution is hosted on a server that you don't have access to. We use Shopify for the majority of our projects and this means we don't have direct server access.
Using a hosted platform like Shopify, Squarespace or BigCommerce gives you the following benefits.
Whilst your server host will typically provide 24x7 support, the support from a hosted solution will include the e-commerce software itself. Many hosting providers won't support the 'application level' of your stack, or you'll need to pay extra for it.
A platform like Shopify hosts over 90,000 stores and they rely on their good reputation for future customers. You can be assured that the software is solid and thoroughly tested.
Hosted platforms are contantly adding new features to improve their platform and this happens silently in the background.
You can jump through hoops to comply with the PCI DSS standard but with a platform like Shopify you don't have to worry about PCI for your online operations at all. It's all taken care of for you.
Shopify boasts a lightning-fast 80 millisecond page response time and this is powered by an infrastructure of 1700 CPU cores, 6 TB of RAM and 200 TB of Storage. On Cyber Monday in 2012, Shopify processed up to 124 sales per second. You have access to this power for a monthly fee between £21 and £121. You can read more about choosing a Shopify pricing plan here.
With that said, sometimes it's better to host your own e-commerce solution. In short, it all comes down to control.
Modern hosted e-commerce platforms are complex and allow you to set up a store that follows best practice. However, in the interests of simplicity, hosted platforms will only include popular features and so may lack something you require. They will focus on their main function, in this case, the catalogue, shopping cart and checkout flow. So you may find, for example, that the content management system that comes with your shopping cart software doesn't fulfil your content requirements. You may also find that there are limits to what the templating language used by your e-commerce software allows.
If your website needs to be multi-lingual and/or multi-national, so users are directed to a different website depending on their country, you'll probably find this hard to achieve or impossible with a hosted solution.
What you need is more complex hosting that let's you run seperate sites on a folder or subdomain and that lets them share common resources such as your product database and customer list. With a hosted solution, you would probably need to set up several different shops to cater for each of the regions you're targetting.
So if you want your web 'property' to consist of several different sites you may want to consider hosting it yourself.
Some hosted e-commerce carts won't let you use your own domain for checkout, since this requires complex SSL set up.
The Shopify app store has plenty of solutions for integration with back end software, such as CRMs and fulfilmment solutions. However, if you're a big retailer, you may find that you need a high degree of integration with your shopping cart software, a level that may not be possible when using a hosted solution.
It may seem like there are more advantages with going hosted, but some retailers will find that their requirements go beyond the hard limits of these providers. It all comes down to weighing up the business case of paying a lot more for self-hosted, based on the benefits above.