The connection speed selector controls Network Hint and whether or not Windows 7 or 2008 R2 Multimedia Acceleration is available.  Its an inherited setting from the MS RDP protocol in this case.
WAN (10mbps or higher with high latency vs regular 10mbps It looks like the options that are selected is the same.  What is technical difference between them?  Should we be using the high latency for 20-50ms connections to reduce text lag?  What side effect could this have? 
Performance Connection Type