WHMCS MU Sub domains vs Sub directory

Hi, I’m new to WP Multisite and I’m trying to figure out the best structure for a business offering.

We have a primary domain (example.com), and are looking to host WP sites (mobile landing pages) for many businesses. I’m trying to understand if business1.example.com or example.com/business1 is a better architecture. I understand there may be a limitation for using the sub domain structure if we grow to hundreds of hosted businesses, so I don’t know if there is the same limitation on the example.co/business1 structure. The sub domains I’ve been experimenting with (business1.example.com) create the example.com/business1 folder structure in the directory, so is it really different?

I’ve researched this, but I haven’t found any clear direction. I’m sorry if this is really basic, but I’d like to go into this setting it up correctly. If you have anysuggestions, or links to information, I’d sure appreciate it.