Let me say this right away – OroPlatform is best to build a multi-tenant b2b business app and you will find why in this write-up.
For those who don’t know what OroPlatform is, here is the quick introduction
OroPlatfrom is a Business Application Platform which has a multi-tenant architecture built into it. Just not that, It is Open Source Business Application Platform (BAP) built on top of proven PHP framework – Symfony. Its frontend architecture is very well built around JQuery & Backbone JS (Chaplin JS to be particular)
With that said, I would further explain why OroPlatform is the best for SaaS Apps – without being too technical.