I set my webshield to normal and Standard to High but I don’t know about NetWork Shield, what is the best recommend setting for Network shield? Normal or High, what are the cons for having it on high?
As far as I know the slider bar (normal-high) has nothing to do with the efficiency of Network Shield. It has the same efficiency level whether the slider bar is set to nornal or high.
Oh yeah I almost forgot that normal or high settings are no differance, but it’s dosn’t mean it’s useless to detect and block worm attacks ;D
Definitely no. Network Shield really works in the real-world and has protected me several times when I get my notebook connected to several wireless lan. 
On or Off, are really all you need worry about (No difference in sensitivity), leave it as the default setting, unless you want to disable the Show warning messages or logging.
The slider bar sensitivity (Normal and High) has no effict here…