I've used MS Dynamics CRM on a limited basis.
Along with Scribe for data syncing with Epicor.
Sales are the main users basically using Dynamics for customer calls, pipeline.
I think you can search this group and find some good conversations on both.
Dynamics looked really nice but once I got involed in customizing and integrating it could feel immature at times. The online version is more difficult to work with too.
Not sure if this is still true but when I was trying to customize comments, they were Sharepoint entities and not exposed.
I'd recommend you get your key fields for Cust, ShipTo and Contacts straight between Epicor and Dynamics before you do anything else. Then Scribe is pretty nice once you are used to the syntax.
Sync Epicor and Dynamics using .csv files or ODBC.
I guess overall I'm neutral on MS Dynamics.
This reminds me of an old CRM package I used to like.
Around 2000 Epicor had a CRM product called Clientele - that integrated with Dataflo (sort of).
I wonder if they still sell this product & if it integrates with Epicor?
I remember at the time administration being a nightmare but users liking the interface for the most part.
Good luck