Pros and Cons of SQL Server version?

Access by it's very nature of being a flat file system is naff as a database backend for a forum, whatever your size of forum.

Forums generally work a database very hard so on an Access version it places allot of strain on the web server using allot of resources.

Each time the database is accessed the entire Access database file needs to be loaded into the web servers memory, add to this Access's connection limit on a database and you are asking for trouble.

The connection limit is made worse on web servers with many having a connection pool of 20 shared across an entire server for all Access databases.

This means that you can for very small sites get away with using Access as the backend for a forum, but for any site expecting more than just a handful of posts a week, you should seriously look at using MS SQL Server as the database backend which doesn't have any of Access's limitations mentioned above.

To backup an MS SQL Database, what I do, is install MS SQL Server on your own home machine, then use the 'Export' Tools on the remote SQL Server to backup the database to the SQL Server running on my own machine.

You got the first step right, for the following steps, if you do a search, someone posted detailed instructions on how to Transform you data to SQL.