I run a tiller boat. My color graph is on my console and I turn it when I'm on the bow mount so I can see it. My bow mount has a color flasher. I'm a multi species angler and often times am fishing from the transom with my Vantage. But often times I'm up front on my Power Drive. Since I fish from the back often, having my color LCD on the bow wouldn't do me a hill of beans worth of good a good portion of the time. But when mounted in the back, I can use it from either position.
I typically don't need a very good bow mount depth finder as I'm usually slinging shoreline or structure away from the boat when I'm up there.
Typically when I'm fishing from the back I'm fishing right below or right near the boat and seeing bottom is much more critical.
I guess my short answer to your question is; it depends on how you fish.