[AccessD] SQL Svr BE + Access FE vs. SQL Svr BE + Web FE?

A client has an SQL Server database.  The db and the server are
well-built and adequate to the demands placed upon it.  My concern is
the client.

The database is stored in my client's Chicago HQ.  My client has a
satellite office in California.  The database needs to be accessed by
both the Chicago and California users.  They want a recommendation as
to whether they should use Access as a front-end, or go with a web
interface.  

Actually, that's not true; they want me to validate their existing
decision to build the FE with Access, but I'm not comfortable doing
that.  If I can make a case they'll go with my recommendation instead.

I am leaning toward the web interface.  But to be honest, I'm not
really sure if there's going to be any difference aside from the cost
of deployment.

What difference in behavior are the users going to see if I present
the data to them via an Access FE or via a browser?

-Christopher-