Only with massive bulk transactions (importing 1000 of lines, posting 100's of invoices at once...) will you really notice any difference, and even then, throwing better hardware at the problem would help with that.

Custom reporting is phenomenally faster with SQL.

That's where the conversation started - i am building an SSRS solution by pulling data using OpenQuery in stored procedures.  The issue came when they wanted financials in more real time.  I don't want to keep pulling data from Sage 100 .

Have done 3 migrations within the past 18 months. Migrating to Sage 100cloud removes any price premium from using SQL (aka Sage 100cloud Premium). This is Sage's second iteration of using a SQL backend. Their first version did seem to have performance issues but it was updated to this release many years ago. 

I definitely advise my customers with a need for speedy reporting and large history files to consider Sage 100 Premium.

I usually tell customers not to expect daily processing differences. For example, the speed of entering an order or posting.  

As Kevin points out, the main benefits are reports and anything you used to connect to Sage via ODBC/SOTAMAS90.

Once you migrate that SOTAMAS90 goes away for any external use and you can either setup individual data sources on machines or you can connect directly to SQL using a read-only account.

Presently Work Order and MRP are NOT available for Premium. This is expected to change when 2019 is released sometime in Q1+ 2019.

Most other popular integrations work just fine with Premium (my customers had Starship, Scanforce, Sage CRM, Credit Cards, etc). The effort to upgrade/migrate the integrations to Premium was no more than what it would be for the traditional Sage database.

I recommend against making changes directly to the SQL database using R/W capabilities as those will bypass Sage's posting safeguards.

Sage hasn't done a very good job of issuing specifications around how to configure SQL or what versions to use. This has not been a big issue for customer sites with highly skilled IT Administrators. 

For some sites where they are just getting started with SQL, I created an FAQ that supplements the Sage supported platforms which may be useful as a supplement (not intended to replace Sage's guides or more current recommendations) 

docs.google.com/.../edit