We are a European industrial company that are in the process of upgrade en replace our current Microsoft AX 4.0 ERP system.  Since we have a mix of companies in our business we plan to have two different ERP solutions, one Dynamics365 Business Central for our sales and distribution units and one Dynamics365F&O for our bigger factories.  Is this a good setup and approach? Please give feedback with pro and cons. 

Yeah having a mix of smaller and larger ERP systems is always possible and recommended if such needs exist. Consider areas like the integration between them, resource availability, support etc too

I definitely see a trend of going from one size fits all or best of suite approach to a more diverse and best of breed direction across the board. Doing the same for your finance landscape could make a lot of sense. It is a very different set of requirements you have for running finance of supply chain and running finance for other purposes, thus separating these into different products will help to keep the complexity of the solution down to what is needed. Whether this will work for you usually comes down to how your core processes are running and what kind of governance structure you have.

If your sales and distribution processes are tightly integrated into your supply chain processes and there are multiple handovers, it might be difficult to control the quality or execution of those processes with multiple systems. If you on the other hand have more loosely coupled processes you would be able to optimize your processes locally to each system. So, your system landscape should match your process design as one complete architecture. The same argument goes for data.

Another consideration is your governance model. Is it the same primary stakeholder who owns both solutions including data and processes, or are these delegated to different owners? If it is the same owner a single system might be an advantage, but since you write you have a mix of companies, I assume that it is multiple owners. In this case multiple systems may help the process of deciding which system holds the master for each type of data and how the processes are supported across the systems. Having multiple systems is more complex but it demands the roles and responsibilities are more clear which is always a great help.

Regardless of what you end up doing, a replacement of an ERP system with supply chain support is a huge task, and I can’t tell you whether those 2 Microsoft products are the best match for you. I have experience running Business Central for non-supply chain companies and I think it is a great product for that purpose.