Go to the Garmin website and there is a feature to compare the different models.
I just bought a 276C.
I liked the idea that I could use it in the truck, bike or the boat.
I bought the Touratech base and Ram mounts so that I can install it on both the GS and the HD.
Sure, I have to buy a marine chart chip, but I will have one unit do the work of three.
Your use may be different, so maybe this isnt the model for you.
Theres really no wrong choice.
Now, that having been said, can anyone tell me if Ishould use synthetic or regular oil in my ride? (Just kidding!)