This weekend I flew from Virginia (XSA) up to Stanley, Nova Scotia (CC4W). The weather couldn't have been much more benign on the trip up. I never once saw a radar return but I did finally see some traffic, usually close to the major airport, particularly around NY and Boston. On the way back the weather was a challenge. I could not have completed the trip in 8 hours without the ADS-B function. It was only a little short of awesome.
So what was short? Well, as has been mentioned many times the returns on NEXRAD apparently can be up to 20 minutes old. Even in moderate storms a lot can happen in 20 minutes. The real usefulness of the information is knowing about where you'll run into weather, and if the storm is building or collapsing, and letting you develop options to go around the storm before you encounter it. I've read that NEXRAD will not help you go between cells but it will help you go around them. After about 15 hours of flying near and around weather with ADS-B I think that's sage advice.
On the way home yesterday, ever storm cell we say existing somehwhere within 10 or 15 miles of where I expected it, but none of them appeared where they were depicted exactly. In fact, one cell consistently showed itself right over the mouth of the Delaware Bay and I could see that area at least 15 miles out and it was bright the whole time. But there was a significant storm about 5 miles to the west.
With a few long trips dealing with weather and ADS-B information, I can't think of a better suppliment to help a VFR pilot with weather in the cockpit short of real-time weather information and that will be fantastic. I'm sure that's coming but for now I am tickled with the ADS-B information I'm getting. Twenty minutes is a long delay for weather but its still great information to have if you use it for what it is.
Don