Mark,
I don't know anything about the waters you sail on, but I like to keep my  
boat very basic. Fewer things to break which takes time away from sailing. I  
have a hand held GPS which my wife gave me for my birthday. Because I'm on an  
inland lake and pretty much know every nook and cranny, I use it to tell me how 
 far and how fast I'm going. I never sail in foggy conditions and avoid  
thunderstorms  at all costs.
As for the depth gauge, I don't have one and rely on the centerboard to  tell 
me when I'm getting shallow. If you know the waters where you are going to  
be sailing, it's not like you have a six foot fixed keel to deal with.
 
Rummy