A couple of Christmases ago Cindy gave me a Magellan Meridian Gold GPS device. Since I'm better than the average bear at navigating, I didn't see it as something I really needed but something to play around with. Since then I've found it more an interesting toy than something I really use a lot.
The device is a small and fairly light handheld unit. It has a small but usable screen which displays various informational screens - the most useful one being a map that can show you where you are. The unit can store waypoints of places you've been to or want to go to, and you can store routes connecting these waypoints. The unit can track where you've been, both for later curiosity and for electronic breadcrumbs that you can retrace later. It comes with a moderately detailed base map of main roads in the US and you can buy more detailed maps to download into the unit via an SD memory card. When I bought it I bought the MapSend topo series of detailed topo maps of the US.
In general the GPS has been good for finding where you are, but not good at telling you where to go - unless you download a route beforehand. Trying to figure out a route on the handheld is awkward because the screen is so small. Nothing beats the resolution and screen size of a fold out map. I find to set a route I need to do it on the computer with the mapping software and then download the route to the device.
The biggest use I make of the unit is for our bicycle trips around New England. We usually follow the rides mapped out by Howard Stone and I map them out beforehand with on the computer. I've got a mount that puts the GPS on my handlebars and it all works pretty nicely. Cindy still leads most of the ride in the more conventional manner but the GPS has acted as a handy double check, often saving us from a wrong turn.
On hikes I've found it less useful, particularly as the topo maps don't include hiking trails. This would be less of an issue if I mapped out the routes in advance on the computer, but usually I've done this when I'm on a longer vacation and haven't felt like the effort.
I tried using it to help me get around unfamiliar cities in a car, and found it less than handy. The unit is small to read and again you have to preprogram the route to make it much use. What's worse is that the routing information is just point-to-point as the crow flies - so it doesn't take into account bends in the road.
I've found it generally excellent at getting a fix. About once a year I've run into strangeness - such as when biking through Duxbury I looked down at the unit and it told me I was in Estonia. No wonder the South Shore seems so different.
Just last week I got a significant update to the unit - the new MapSend DirectRoute software. This allows the GPS to automatically plan routes out for you - mark where you want to go and it tells you which streets to follow and when to turn. I've only played with it for a short while, but it's good, bad, and laughable.
The good was well demonstrated when trying to find the start point for our last bike ride. Cindy got lost in the back roads of central Massachusetts (hardly surprising since Massachusetts doesn't believe in road signs.) We fired up the GPS to take us to the (pre plotted) start point and it led us there with aplomb.
I'd already discovered the bad that morning plotting out the route for the ride. The software only allows you to design routes from a single start to a single end - stopping you from setting multi-point routes like our bike trip. This limitation bites you in other ways. I asked it to plot our route from home to the start point, and it sent us down I 93 through Boston, but we like to avoid Boston and take 128. Without intermediate waypoints we couldn't nudge it to do that for us, nor can you set an area of road to avoid as you can in some route finding software. The map data also doesn't know about one way streets.
The laughable occurred on our way home. The unit did a great job of getting us from our bike finish point to a major highway. From then, of course, it wanted to take us on I 93. So we decided to ignore it, take 128, and ask for a re-route once we were heading north on 128. When we asked for the re-route it instructed us to get off 128 at an exit we'd just passed, then get back on 128 in the same direction. I tried several times to re-route and every time it insisted on this strange maneouvre.
Having said all that, I might try taking it with me on the road and seeing if the new software is any more usable in practice at getting around a strange city.