Others say...

"Geocaching use"
I'm not an expert on GPS units, and other reviewers probably are, so I'm just reviewing how I found its use while geocaching (the reason I wanted it). Currently the geocaching website has a feature where you can add a cache straight to your GPS when its plugged into your computer. The data cord to do this is included with this GPS. I used it right away, easy learning curve, no problems (you had to download a browser plugin at the geocaching website).
Creating routes and entering/naming waypoints by hand is easy too. The one thing that disappointed me was I couldn't load additional detailed city maps for it. They don't exist for this unit, from what I could tell at the Garmin website. The accuracy seemed pretty good. Some problems with tree cover, but nothing abnormal.

"How about the reception?"
Just used my new Vista for the first time this weekend in the Rockies, where you can easily need a working/accurate GPS.
The system gave me weak signal notes almost all weekend. I was just a mile or two off HWY 24? Not many trees. Even lower quality further in the mountains just west of Pikes Peak? Ok, I have been around, I will try to figure if it is me, but I have used GPS before and this does not seem right.
Luckily, I always terrain navigate with 1:24K maps I produce from Natl Geo, so a non-functioning GPS is not a big deal, just thought it could help. Hey, maybe I do not need a GPS?? For about $0.40 I can print my own maps.

"Good, But not as good as my old gps.12"
the vista is good, but in trees it looses reception fast, and not in that thick of trees, My old Garmin gps-12 eat batteries, but it never lost satelite reception, but the vista is great in open country

"Hard To Read"
We loved the Garmin and it helped us locate 4 caches on the first day we used it with our 10-year old grandson.
My negative - the numbers are too small and hard to read. If I bought it again, I would get a diferent version.
Check you age and your eyesight when you order the product. If you can read the telephone book in dim light you are almost OK with this model.

"Good features, but screen refresh is too slow, not good for car"
I had a Magellan SporTrak Map GPS before I got my Garmin eTrex Vista. I bought the Garmin because I needed an additional GPS as my two sons were constantly using my SporTrak for geocaching, and I always like to keep a GPS in my car for those times when I need a quick detour, or need help getting somewhere and I don't want to miss the turns. I had read in a number of reviews that the Garmin units were more feature-rich than the corresponding similarly priced Magellan units, so decided to get an eTrex for my car, and let the kids keep my Magellan.
Here's what I found. The features are good, 24MB of map memory compared to my Magellan's 6MB. The waypoint siteline (the line it draws between you and your destination) properly moves *with* you, instead of the Magellan's wacky fixed siteline that stays put from the moment you set a waypoint destination. Good screens, I like the fact that you can customize it so that the satellite accuracy in feet can be displayed on both the map and the navigation pointer screens (good for geocaching).
But as it turns out, this unit is completely inappropriate for use in a car. The screen is too small for use in a car, the light is way too dim, and the redraw is *way* too slow. If you scroll the screen a bit just to find out what roads are up ahead, you will wait 8 seconds (sometimes longer) just for it to repaint! The only way to avoid this long repaint time is to zoom out so that not as many detailed roads are displayed, but then that defeats the whole purpose, since you then can't see the smaller roads that you're interested in.
The items that this unit falls short on compared to my Magellan SporTrak Map are:

-Incredibly dim light, not very useful unless your eyes are 3 inches from screen
-No audible beep feature
-Very slow repainting
-Very clumsy panning (slow to move the cursor, and once you move off screen it repaints, causing a long wait).
-Small screen

In order to get the detailed maps, you still need to buy the MapSource software. I got the MapSource Metro Guide USA, it has detailed roadmaps for all of US.

The features of this unit that are superior to Magellen SporTrak:
-Waypoint siteline moves with you
-Shows satellite accuracy in feet
-Much more space for maps (24MB)
-Built-in compass, keeps you oriented even when you're not moving
-Longer battery life (12 hrs)
-Small, fits well in pocket

All in all, a good unit, but not useful for driving when you need *quick* response in order to avoid taking your eyes off the road for too long. For geocaching and hiking, I think this is a very good unit.