Garmin has been in that business for a long time, so it has had the time to polish the user interface. Not all Garmins have an identical interface, but once you understand the interface on one, you will easily pick up the interface on another. If you have a relatively recent model, like within five years old, if the user has an interface problem, it is generally because they didn't bother to read the user guide first.
Also, if you buy a GPS receiver that is intended purely for one application, like car navigation, and then if you try to use that for a completely different purpose, you are likely to find lots of interface problems mostly from your own head.
I have one Garmin model that can be set up to do car navigation, or else you can set it up differently to do hiking or geocaching or something else. It takes only a few seconds to switch it over from one to another. However, if the user forgets which way it is set up, then that makes problems as well.
"Do newer garmins have better mapping capbilities?"
Better than what? What kind of mapping capabilities do you seek?
The single biggest weakness of a typical GPS receiver is the small size and resolution of the display. You can see only maybe 1% of what you can see on a large paper topo map. As a result, I don't even try to make my GPS receiver compete with the large paper topo map.
The next biggest weakness is that of the map database. Typically there will be all sorts of minor errors in the database. If the company is giving away that database as a feature of the receiver, then that means one thing. If they are selling it, that means something different. Very few will do major updates of the map database simply because there is no profit in it. If you are a backpacker trying to follow a trail, you should not need very much of a mapping database. If you are trying to go off-trail, then topography gets much more important, but the topography is unlikely to be changing or needing updates.
Once every year, I try to do a head-down exercise where I watch only the GPS screen and try to go where I am going without looking at the surrounding terrain. Most of the time, I backpack purely head-up with the GPS receiver turned off.
To paraphrase Yogi Berra, "You can see a lot just by looking."
There is a lot to be gained by learning to read a topo map and do most of your navigation that way. The GPS receiver makes a good backup system since it will operate with no visibility or in bad weather. During bad weather or bad visibility is when humans need the most help, and that is where the implications of getting lost become the most severe.
My concern is that too many people can do land nav only with their face at a screen, and they can't effectively navigate by traditional methods. Once batteries crap out, they are in trouble.
I once hiked with a guy who had some Garmin model with a barometric altimeter feature. The question is: does the barometer adjust the GPS altitude, or does the GPS altitude adjust the barometer? The answer is that it could go either way, but if the user doesn't know how it is set up to function, then you don't know what you will get. This particular guy got into that situation, and he was cursing the receiver until he finally got frustrated and turned it off. Well, that was because he didn't read the book and try to understand.
I taught specialized GPS classes for almost 15 years, so I learned (1) how to get the best results out of my own receiver, (2) how to troubleshoot the other guy's receiver, and (3) how to teach the other guy so that he understood [and so he didn't bother us anymore].
Some of the worst cases of GPS understanding happened in some people with the highest educational level, so don't feel pregnant.