I just bought an eTrex Vista and I've been pretty happy with it, but I must say the 'Area Calculation' feature is essentially worthless. Out of nearly 100 calculation attempts and two calls to Garmin customer service it has worked twice.
Symptoms: After pressing 'Start' for the Area Calculation, walking the area, then clicking 'Stop' it returns 0.00000 for the area (regardless of the selected units).
Garmin Solution:
#1 Do a master reset and let it sit out turned on for 30 min. acquiring satellites and try again.
#2 Ensure that you have no other tracks active on the map screen, because they will be taken into the area calculation. Make sure when you complete walking the area, you cross over the exact 'Start' point, by overlapping it by at least 3-4 feet.
Regardless of trying either solution the area calculation program fails to function even in a remotely useful way.
Again, I'm really happy with the Vista and I wouldn't have bought another brand of GPS even if the Vista didn't have the Area Calculation feature. It fits perfect on my road bike and on the dash. It's as small as my cell phone, which makes it easy to drop into my pocket. I'm impressed with how much you can tweak the look of the screens to suit your taste.
That said, I wish they would have left the 'Area Calculation' feature off the unit. It is frustrating to me (coming from a product design and development background) to understand how they could even incorporate such a poorly functioning feature such as the 'Area Calculator' into their product. It detracts from my image of Garmin being the quintessential leader of the consumer GPS market, because it shows a lack of design discipline, and/or a product that has been hastily brought to market. These factors are inclusive of some important design "tollgates" that have missed in this product development.