1- Specialization

OroCommerce It was created specifically for the B2B world - by default, it contains materials and features integrated with the default Architecture - engineering of the system.
BigCommerce and Shopify B2C is initially provided with the features of B2B - B2BBundle For BigCommerce
It's known that specialization makes the difference in quality and adaptation.  

2 – Open Source Vs SaaS 

Small Medium and large business - OroCommerce will be allowed to develop freely without additional restrictions imposed by SaaS platforms, stores which has deep development and care about the extensive capabilities offered by OroCommerce Open Source platforms also for small store which search quick development and need open platform the open source is solution with OroCommerce  .

3 – Free Community Version

OroCommerce came with free community edition which offer almost all features needed by  medium and small companies , every one can install try and start using it , 

4 – CRM included with OroCommerce

CRM included with OroCommerce helps you organize sales pipelines, segment customer base, and determine marketing and sales projections for your business across multiple channels.
Main CRM Fetaures:
    • Manage Leads
    • Manage Opportunities
    • Manage Marketing Lists & Segment Customers
    • Manage Email Campaigns
    • Manage Calls Tasks & Cases .

5 -  Deploy-anywhere

A deploy-anywhere approach enables deployment in any Cloud environment and on-premises. even with small host package for small stores .

6 - Store Shut Down For SaaS 

Might your Store get shutdown by SaaS team or Automatically and sometime without notice , may they think that you're a scam and took down the store for a reason of doing a security check because you're a new seller. Otherwise with Open Source project like OroCommerce For B2B Your have the Code and Data To make your store works by hand .

7 - Multilingual store 

Shopify and BigCommerce doesn't offer a native solution to create a multilingual store , Otherwise In the Oro applications, language is a core component of system localization and content translation Even for free community edition.