I am a scout leader who trains other leaders. I am also an avid outdoorsman. Earlier this year I participated in a week-long youth leadership development camp where we showed the boys how to use the entry-level Garmin GPS. They took to it quickly and were able to navigate around the camp to find geocaches and waypoints. I spent a lot of time with the units marking the waypoints for the boys to find.
So, when it came time to buy my own, I was already familiar with the basic Garmin layouts and such. In comparison to the basic unit I have LOVED my eTrex Legend. Some of the features that have been very handy:
1. The addition of a navigation button allows for MUCH easier data entry (i.e., plugging in the coordinates for a waypoint, labeling waypoints, and navigating around the menus). This button is almost worth the price difference between the two units, especially if you need to enter a lot of your own coordinates manually. If you only use it keep track of where you've been and find your way back (i.e., to your car on a hiking trip), and you don't care much about labeling things, then this feature isn't going to be as big of a deal for you.
2. The base map is nice to have. However, be aware that the map doesn't have a number of state or federal roads and highways that you would hope it to (and don't even think of using it for finding things within a city). Moreover, some of the highways it does have are completely inaccurate. For example, we were on a back-country backpacking trip a few weeks ago and the GPS map showed us crossing over a highway that a) doesn't even leave from the town the map shows, and b) definitely doesn't cross over the mountain range where we were hiking. Bottom line: don't think that this unit will completely replace the need for a map and compass.
Some things that would be nice to improve on the design:
1. No direct compatibility with Macintosh computers. The cable that comes with the device is a serial cable instead of a USB. You can buy a USB converter, but with the prevalence of USB in the market, it just seems like that would be a better format. From what I understand, this is an issue with most of Garmin's products.
2. As nice as the navigation button is, there are still a few things that are hard to navigate through on the menus. I would like it to be easier to mark a waypoint without having to scroll through menus to get to the "main menu" and then navigate down to the "mark" icon in order to mark a location. Also, while I love the "find" function (built into one of the side buttons), choosing "waypoints: by name" takes you to a keypad screen that I have found hard to get out of. You select the letters from the keypad to spell the waypoint you are looking for, but once it is up on the screen, you can't just scroll up to it and select it ... you first have to exit out of the keypad. It may be a small step, but when you have what you are looking for on the screen, it is a frustrating extra step.
All that said, the unit is small, light, and fairly easy to use. And has seemed to be quite accurate. It saved out bacon in the back-country when we lost the trail and had to bushwack for a couple hours till we were able to find it again. Don't know how I ever got along without one!