Garmin nuvi 255W Car GPS Receiver

I bought this unit and used it locally for a few days before taking a major trip from the Bay Area to Grand Teton/Yellowstone park. It performed just fine around the local area.
However, it got lost in Twin Falls ID and kept taking us around in about a half mile circle. It never could find the freeway again and we finally had to stop & ask a stranger for directions to the freeway. Then, it kept losing satellites going from Twin Falls to Idaho Falls.
It did navigate us pretty well into the park right up until it told us to turn right to enter Jackson Lake Lodge when in fact we needed to turn left. That was almost the final straw.
Coming back across I80 through the salt flats of Utah and across Nevada, it would often report that it had lost the satellites. There is no excuse for losing the satellites in that wide open country and that was the final straw. It went back to Sam's Club when I returned home.
Sam's was great about it and promptly credited my card.
Another annoying feature is that it does NOT calculate miles per gallon. It expects you to enter your milage expectation and then calculates how far you have to empty. I say that is backwards. I want the computer to tell me my mileage, not use the often incorrect manufacturer's number.
Short story, don't buy this unit.