...upgrading to SQL Server is the ideal way to go, with numerous advantages over an Access back end.
I've read this opinion and general advise many times. Sorry, but sometimes I feel obliged to add:
... and potentially numerous disadvantages.
There are many different situations in respect to clients, applications, distributions etc. especially in the Access business area. As consultant and developer I repeatedly have experienced how the change to SQL Server (mostly demanded by IT as principal
not by exigency) has complicated if not deteriorated things for all parties.
Many of my clients are amateur Access developers (often at a rel. high level) who create and maintain databases for their needs or departments. SQL Server makes them much more dependent on the IT departement for which in turn they are unimportant. They are
usually not part of IT and not integrated properly. Now they often get additional delays and friction losses with technical and organizational problems (wrong ODBC drivers, permissions etc.).
The independence (or being under the radar) with Access-only solutions isn't always and from every angle a problem but very often a big asset of the tool and for the users/developers.
Another wide spread and important fact is the lack of knowhow:
SQL Server demands an additional rel. high level of expertise that Access people often don't have or only partially, i.e. have to acquire themselves in a rough and ready way without a budget or training. Thereby with SQL Server they may get more problems
and errors with performance, data types, drivers, backups etc. than what they get as advantages. I'm not talking about the great theoretical possibilites but about the real use I've often seen.
Even if you only deliver applications to clients it doesn't become necessarily easier to install, distribute, run and maintain them with SQL Server.
It very much depends on the possibilities you get to act and intervene and on the partners you have at the client.
I have migrated applications to SQL Server and do development work and training for clients who use SQL Server. It can be a really good thing. However, I don't subscribe to the general and "ideal" advise to migrate but to only do it if there is a real need and
advantage, or let's say, to always consider the pros and cons as carefully as possible before you migrate.