The first unit I bought was a Garmin Nuvi 1350. I really like this little unit and it has proven to be very accurate for geocaching. It's slim and easily fits into my pocket or back pack.
To use this unit for geocaching, all you have to do is plug it into your computer with a USB cable and go to any cache page. Click on SEND TO MY GPS and it will send the location to the unit. Disconnect the GPS from the computer, turn the GPS on, go to MY FAVORITES and choose the GC number for that cache. Highlight it and you're ready to navigate to the cache. Very easy to use. My husband likes to use it on the turn by turn feature, which is a good feature to use when driving to the geocache location. But I prefer to use it in the Map feature. When we get close to the cache location, my car icon turns into a small circle that moves closer to the cache. I've found that this unit is accurate to within 15' - 20' of the cache on a clear day when the satellites are locking in. That's close enough for me and we find more geocaches than not.
Here's a link to the Nuvi Spec page. This unit generally retails for about $ 100.00. I've had this GPS for about 4 years now and it's been well worth the money. It has an accessory that lets you attach it to the dashboard or the windshield and can be charged with a wall charger, a car charger or a USB port. The only downside to this unit is that it doesn't run on external batteries - meaning that when the charge runs out, you have to physically plug it in to re-charge it. I find that a full charge lasts about 2 hours. This is a downfall when we're out in the woods and the charge runs out. I wish they would make this unit so that it would also run off of AA batteries. That would be sweet. It would also be nice it they'd add a way to attach a lanyard so I could hook it onto my backpack or hang it around my neck.
The other GPS we use is an Oregon 450. You're probably wondering why we need 2 GPS units. Well, the Oregon makes it possible to do paperless caching. That means we can down load most of the cache page information directly onto the GPS, as well as get directions and the map features.
The Oregon comes preloaded with a worldwide base map, it's very sturdy and it's waterproof. I know, I dropped it in a stream. It also has the ability to wirelessly share information with other Oregon devices. This is a super feature if you're out caching and meet up with other cachers who have different caches loaded into their unit. They can quickly transfer their information to you and vise-versa. It's a handy feature that I've used many times. You load your caches the same way, just by sending the file to your unit from the cache page.
The Oregon also lets you record if you found the cache or not. The thing I really like about it is that it runs off of 2 AA batteries. I use rechargeable batteries and when we go caching I always toss a spare pair in my back pack, just in case. More often than not though, the batteries last all day. They advertise 16 hour battery life, although in my experience it hasn't been that long. But with my spare pair, I've always been fine.
Another great feature about this GPS is the tracking feature. It keeps track of where you walked. Case in point - I was out caching with some friends and one of them dropped their camera someplace in the woods. We turned on the back track feature and easily retraced where we walked, eventually finding the camera several blocks back.
The Oregon 450 is a bit more pricy - it generally retails for around $ 250.00. It's also pretty accurate, usually within 10'. Here's the spec page if you'd like to take a look. It also comes with a carabiner clip so I always have it within easy reach - it hangs off my belt, backpack or on a lanyard around my neck. I really like this unit and I'm happy I invested in it.
So, which one do I recommend? Well, I think it's a personal choice depending on what features you'd like. When we began geocaching we started with the Nuvi because it was a low cost investment. We found it accurate but didn't like the low charge life. We also had to print out the geocache pages and take them with us when we went. Once we became more experienced and realized that we'd be geocaching for awhile, we decided to invest in the Oregon, mainly because of the paperless caching feature. It's nice to plan a trip, download about 100 geocaches and have all the information at my fingertips.
There are other versions of both the Nuvi and the Oregon out there to choose from. Most of them work basically the same with varying features, so take the time to read up on them a little before you invest.
I do want to point out however that having a GPS isn't necessary for finding a geocache. My sister found her first 100 geocaches without one, just by studying the cache pages and maps, reading past logs and looking at the hints. But if you're going to be out in the woods or the wilderness, I highly advise getting a GPS. Most GPS units will help you to locate the caches a little quicker, mainly because they generally help to narrow your search field.
(This post was an informational post based on my GPS units and experience. I wasn't asked to review these products nor was I compensated by either company to talk about the products.)