If you’re otherwise invested in the Microsoft/Azure platforms, you probably should. This is all anecdotal (as a marketing automation dude I tend to talk to CRM dudes and dudettes a lot), but I hear Dynamics is easier to use than Salesforce. Dynamics is also cheaper than Salesforce and (for now) more open in terms of integration.
Salesforce is top-dog in the CRM market and they’re acting like it. They want you to use the products they prefer, which I suppose makes senses from a business perspective (even if it’s less convenient for us, the consumer!).
So if your organization also uses Office 365, you might gain from the move. However, if you’re not in the Microsoft ecosystem, it’s harder to come up with a good reason to move to Dynamics 365. You already know Salesforce and 90% of enterprises use it.
If you’re a consultant, you’re good either way. Both markets are booming. I figure you’ll likely be able to use your CRM-knowledge gained in Salesforce and apply it to Dynamics (even if the specifics are different). This is certainly true in marketing automation, I don’t see why it shouldn’t be true in CRM.
I first answered this question on Quora: