This all depends on the size of your store. If you are just starting out you can get a feature-rich store on Shopify for $29 per month. You'd be surprised how many features they provide. For small to medium sized business, Bigcommerce is also a good option. If you are a bigger company, both Shopify and Bigcommerce have enterprise-level options as well. There are also some free options like WooCommerce, which is a plug in for Wordpress.
There are many factors that go into that choice. I haven't heard of those 2 options and I have been in ecommerce for 20 years. That being said there are many ecommerce platforms that have cropped up in recent years. I personally prefer Shopify.com for most businesses, due to the functionality, cost, and another nice factor is that they host everything their cloud so you don't need a separate hosting account. Shopify has a wonderful app directory that has plugins to add functionality to your web store. Once you have a theme picked out, you add some apps, load up your products and you are bascially in business.
For what it's worth, I've been in software development (mostly ecommerce, mobile and custom apps) for the last 10 years and have never heard of those two platforms. I've worked with dozens of companies from cocktail napkin fashion startups to multi-billion dollar household brand names, and selecting the platform for your needs almost always follows the same cadence.
Common answers will include Shopify, Wordpress (with a plugin) and go onward to things like Demandware, Spree. In my experience Magento is the best all around when you consider scalability (especially with the simaltaneous transaction volume they can support with the expansion on the 2.0 platform.) Plus it makes mobile commerce (native app) more feasible. ultimately though ecommernce platforms are a bit like school - most people will graduate from one to the other (going from a simple solution like Wordpress to Shopify then Magento then maybe cmpletely custom etc) as their business needs grow and their company expands. Other factors you should consider when choosing platforms include overall cost, access to developer talent, access to support, existing modules and tools available, whether you want to integrate and have a brick & mortar sales presence as well (and so on and so on.) a lot of considerations to keep in mind, but finding the right platform for you is very doable with the right research.
happy to help and discuss further and help guide you down some options that fit your specific goals.