A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
Hi Clynk,
Each site collection has its unique metadata, while subsites inherit all these properties from the top-level site in a site collection. So in other words, if you setup metadata or navigation or security groups or adjust site colors and logos on Site Collection A, you have to manually repeat all of it on Site Collection B, should you decide to proceed that route.
When you are in the following scenarios, you can create subsites.
1. Create a site with same metadata, security or navigation as the existing sites you already have.
2. You are a small organization.
3. Keep same look and feel as the template site.
4. Have a handful of SharePoint sites in your organization.
When you are in the following scenarios, you can create site collections.
1. You are a large organization with multiple business units and each business unit has independent and separate business functions.
2. You are a large organizations and each of your departments has a large number of people and each department is expected to create lots and lots of sites.
3. You are a large organization and want to separate your SharePoint administrative functions. (Separate SharePoint administrators for each site collection)
4. Your organization has lots of content. (Server resources and storage)
5. Share content externally.
You can decide which one is better according to your scenario. You can refer to this article for more details about sites and site collections.
Besides, about "the drop downs below are limited", can you provide related screenshots about it?
Regards,
Yoga