I bought this as I wanted to go paperless with Geocaching. It was the lowest cost Garmin product (my preferred manufacturer, no other reason) offering this feature and to be honest, the additional features of other units didn't justify their unbelievable costs; especially the Dakota 20. The extra money seems to go for an SD card slot, magnetic compass and pairing!!! Big deal. As you can connect to the Dakota 10 using USB, and it has over 800Mb of internal storage the SD card is not a requirement of mine. The compass works fine when moving, so that wasn't an essential need either.
I have been using it for a few days and what a Geocaching revelation it has been - having cache descriptions, hints, logs available on the unit is a HUGE improvement from printed or remembered details. The 'Accuracy of GPS' field is helpful too when searching for that elusive microcache to get an idea of where you need to look. You do have to upgrade to be a Premium Member on the Groundspeak website, but it's well worth the $30. Once the Pocket Query results are copied into the relevant folder on the device, there are tons of caches and their information available at the press of a few buttons. Plus, there are Premium Member only caches - nice.
The interface is nice and customisable and I especially like the way you can add/remove/reposition all the menu items per profile. The trip computer is great too as you can decide exactly what you want to see, as you can on the maps and compass too. As I am primarily a Geocacher rather than hiker/walker I have not explored the route/track options to a great degree, but they look good and I will be getting into them the more I get out and about.
Now - the downside. The basemap that comes with it is....well, it rhymes with 'map'. As a previous reviewer has said, this isn't good enough; I agree 100% - the map is unbelievably poor and the costs of commercial maps are outrageous given that it's an essential part of a GPS. This device SHOULD come with a decent map - sort yourselves out Garmin. It did feel like buying a book with an amazing cover to discover that it only has chapter headings in it and no story. However, as Martin wrote on the comments to this other review - FREE maps are available to put onto the device. I followed his fantastic advice and tried it out and the results are terrific (thanks Martin). Just Google "talkytoaster" and follow the instructions.
The battery life is great, the interface is great, the features are great, it's great!! For the Amazon price you can't go wrong if you want to take your Geocaching to the next level. Go on, treat yourself.