I have the Garmin 4208 with these capabilities and it is unbelievable. I update my card online and now have the 5.10 and they have done some very nice updates. It's like driving your car on the water, very cool!
The radar is also nice with the black background and the yellow targets. If I set my range for 1/8 mile I can see lobster pot bouys easily.
Garmin Rules!