I love Shopify and Shopify Plus, have worked with their team very closely on many large re-platform projects and I have to say for B2B it is getting there, very slowly, but still miles away from being B2B enterprise-ready without a significant amount of custom build work, hacks, apps and workarounds.

There are so many issues with Shopify Plus for B2B use cases that it's hard to recommend unless the store is very simplistic.