From my experience and preferences, I would schedule with meeting with my fleet/internet manager before I come if I want to test drive something. If I just want to browse around then I don't schedule an appointment. I don't deal with salemen anymore, it's a waste of time.
PS...I bought my car there a year ago and had a good experienced.
2013 GLK 4Matic - Self
2011 GLK 4Matic - Wife
2006 BMW E90 325i - Self