Andrew and Andy are both right – the decision of which environment to go to really depends on your risk tolerance AND whether you want to receive all the updates that online has available. We chose online knowing full well that there is a risk of outage due to shared environment, performance challenges on a shared tenant, and the need to use fetchxml and apis to access any of our data in the cloud. We are a technology company with tens of thousands of servers – so infrastructure/DR/Business continuity weren't concerns (but the costs are always a factor in it). The benefit of having on-prem is clearly the direct access to tables and the ability to use more advanced join capabilities that SQL offers – plus more ready access to critical information like audit tables. Another aspect of online that needs factoring in is the tightening that Microsoft has recently embarked on for API limits per user – in a shop like ours where we have thousands of users and a lot of integrations this is about to cause real heartburn for us – something that isn't a factor in an on-prem. Start from the perspective of drawing out the key elements you want to achieve and what your risk tolerance is for each. Best of luck in your analysis and decision – there is only 1 wrong way to go in this (and that is selecting a CRM other than Dynamics).
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