What is called "Modules" here is more a hack to modify the shop.
Good thing on modified, if you are programmer, you can implement nearly everything you can imagine.
The code is not too complex and the community often helps very quickly to find the proper code part you are looking for to modify it.
Bad thing .... at the moment the default template is not a responsive one. So you have to design your own, choose one of the free or buy one .... and they might have some bugs.
Little bugs are also in the default template, but easy to fix and you find everything about this here in the forum.
Example is a <p></p> around the product description and the editor also places a p element so you get this invalid code:
<p><p>your description</p></p>
If you buy something, make sure first, (if required for you) multi language implemented or not .... some guys just write some code for their own and make it public then and others then find out the guy ignored the multi language part. You also could implement the multilanguage then by your own, that's easy in the most cases. I only wanted to prevent you from a suprize
Welcome on board!