Our main app is an Access front end with a SQL back end. The connection between Access and SQL is ODBC. This can occasionally be prickly. Many of our customers are the Express version, larger customers use the Standard version. It's quite a jump from zero to whatever Standard version costs now.

We install an archive database which is more or less a mirror of the production database. Once a month we archive historical data into the archive database and purge from the "OLTP" database. That helps to keep the OLTP database under 10 GB. The OLTP database typically has two years of history.

Express has been rock solid. I don't believe there is any reason why it would not be as reliable as Standard version or higher. We use Ola Hallengren's script for backup and optimizing and trigger it via scheduled tasks.