Auto portable GPS's have a constant upgrade buy trap.
Started with a $200 Nuvi 200, Upgraded to a Nuvi 770 with some more whistles & bells, Added lifetime map update over a year ago.
Now want a 1490LMT http://www.samsclub.com/sams/shop/product.jsp?productId=prod2100023... with even more whistles and bells, or even better a 3790LMT https://buy.garmin.com/shop/shop.do?cID=134&pID=87930&ra=tru... with even more whistles and bells.
When just passing through it would have been handy to know which lane to be on to make the new route or to stay on the old route.

Really would like a WAAS feature, as the above mentioned have a +/- 50 feet accuracy, while their WAAS has a +/- 5 feet accuracy.

On our trip to California for the California Alfalfa & Forage Seminar that more accurate location MIGHT have saved overshooting a turn a few times. Driving in a totataly strange area, with new roads hidden by almond trees I crawled past the hidden new roade a time or two. That 50 foot thing could make a difference

Buying from SAM's Club can save +/- $100 over buying from Garmin.com if you are happy with what SAM's is offering.

I have noticed it does require about 8 hours to down load to the computer a map update, and then another hour of two to teach the little toy where the new roads are. After an upgrade it does require maybe 30 minutes to boot up the little toy.

Irrigardlessly it is a good idea to have someone in the right seat with a map in hand to keep track of where you are, and to watch for changes. To ask it questions, and to change modes so the driver does not feel the need to take their eyes off the road. Not in that traffic and on those roads!

Suggestion: Rather than discarding the an older Garmin toy use it at the same time you are using the newest one to find the way, (Navigate). This way you can navigate looking at a mile or so, while also seeing a small scale display that is has a 30 or 50 miles range. My 770 does not show speed when in navigation mode nor does it show heading. The old useless Garmin fits this need.
The 14xx and 37xx has a speed limit plus a vehicle speed side by side, which is a help. If I upgrade to one of these I will still keep a second older toy for a small scale display.