My review comes from the perspective of an IT professional who works for a Microsoft Dynamics reseller, so I guess I have a certain amount of bias. That being said, I have been using Microsoft Dynamics NAV and here is what I like best:
Firstly, it is really easy for the developers to work on. They have access to all the source code of the system and a development environment is available out of the box. Additionally, there is an entire module of the system (RapidStart) devoted to helping the IT professionals migrate data into your system during your primary implementation. Additionally, from a developer's perspective, there are a lot of pre-packaged functions in development environment making it quick to do development that might take a bit longer in other programming languages.
Secondly, it is very easy to get data from the NAV system by creating queries/pages and oData feeds. These oData feeds will allow you to access your data from Excel PowerPivot, PowerBI, or other similar tools.
Thirdly, I like that the user interface is very easy to personalize (i.e. add and remove action buttons, fields, navigation buttons, etc. and create personal views of data to see later) and also your IT department can add and remove fields, pages, etc. from user interface for entire groups of users. Additionally, elements of user interface are automatically removed based on your license configuration and permissions of users.
Fourthly, in general the user interface is very attractive with large nice-looking icons, tiles to direct users to the tasks they need to do each day, etc.
Fifthly, as I understand it, NAV offers very good value compared to other systems. It is fast to implement and offers wide functionality.
Fifthly, Microsoft has a roadmap for this solution and is releasing updates every month and a major release every year (which is good). They have also done a lot to make the solution easy to upgrade.
Firstly, I think the charts feature in NAV is not as great as some other solutions I have used (but they make up for this by allowing you to embed a PowerBI dashboard into your system in latest version of NAV).
Secondly, the workflows feature is not as good as in Microsoft Dynamics CRM (then again it may be better than other ERP systems, plus it is possible to integrate CRM and NAV together which is nice).
Thirdly, sometimes it is challenging to understand the link between the various types of ledger entries in NAV, but this might simply be a challenge in any ERP system. It sometimes is challenging for example to reconcile the G/L with inventory ledger if you are using any of the features such as automatic cost posting to G/L, automatic cost adjustment, and expected cost posting. Additionally, in some versions it is not so easy to reverse invoices, but they have made up for this in latest version by allowing to cancel or adjust invoices (while still keeping a complete audit trail).
My employer resells this solution, but also uses it for our own accounting. The main problem is keeping track of accounts receivable and A/P, keeping track of expenses, etc.