I worked with Dynamics GP for 7 years as an accountant, an IT admin, and an SSRS report writer.  I also have extentsive experience in Dynamics AX and Dynamics NAV.  I can honestly say that there is no benefit to using GP instead of NAV or AX.  I know the GP application and database like the back of my hand.  So I know whereof I speak when I say this:

GP is an old, clunky, bug-ridden product that Microsoft has never really fixed or updated significantly, and they never will.

Here's one example.  In accounting, if you enter cash receipts, then later enter a consolidated deposit, you are required by basic GAAP principles to have an "Undeposited Receipts" GL which will hold the receipts prior to depositing them.  That way, you don't throw your bank GL out of balance with its subledger between receiving funds and depositing them.

Unfortuately, GP doesn't follow this most basic principle.  When you receive payments, it puts them directly into your bank's GL, even though there is no such entry in your bank subledger yet.  The GP deposit then affects the subledger, but not the underlying GL since it's already been done previously, bringing it back into balance.

Since cash receipts and bank deposits have separate editable dates, there is no way for GP to ensure that your bank stays in balance.  If a company processes receipts on the 15th, 16th and 17th and then does a deposit for them on the 18th, the bank subledger will be out of balance with its GL for 3 days.

This is basic accounting.  Yet GP has never bothered to fix a hundred different ways that it creates imbalances between its subledgers and GLs.

Worst of all, instead of actually fixing other bugs in GP, they created the band-aid "Reconcile" feature to fix the data tables in GP that regularly get screwed up (inventory totals, GL summary totals, orphan records, etc.)

If a business needs something equivalent to GP, they should go with Dynamics NAV which Microsoft knows is a much better product since they have incorporated it into their Dynamics 365 product as "Dynamics Financials".  NAV was better 15 years ago than GP is today.

If your business is outgrowing GP, go with Dynamics AX.  It was an excellent product in 2009, and then Microsoft reworked it in 2012 into a brilliant and robust ERP system that can compete with SAP and PeopleSoft.  AX is where Microsoft is putting most of its resources.  It is their flagship Dynamics product, knows in Dynamics 365 as "Dynamics Operations".  As far as Microsoft is concerned, AX is the future.  GP and SL are trash that -- in secret -- they only support grudgingly.