Summary: I've had mine a little over a year now, and I have been disappointed in the unit. For me, the major limitation is the speed (lack of) of the processor. It is very slow in getting a fix, and in showing your movement. My main use is in a 17' boat used for waterfowling. I was finally frustrated enough that it is now my backup until I can find a more updated handheld gps.
Summary: I purchased this GPS unit and was expecting it to be good to go, just like my last Garmin GPS. I was wrong. The preloaded map is awful, the unit requires a micro sd card to download any of their maps including one that was free with my unit. The website is confusing and the download process is entirely unintuitive. It reminds me of software installs back in the windows 95 days. Not to mention the maps I need for hunting, hiking, and driving would total around $200.00.
Summary: I have had a few weeks to check out this unit and find it does everything I need, and does those things well. Quick start up time...rapid signal acquisition...accurate positioning. If you're looking for a great GPSr for geocaching, this one is well worth the price.
Summary: For me this was an upgrade from the Magellan Meridian Gold. There are some things that the 510 has that are better and also far worse. The better: 1) The built-in entire US map--I used to have to manage how much of the country was loaded. This is a big time-saver. I'm not sure yet of the detail that would be provided outside of the US. Hopefully it is better than its predecessor that only had city points and few roads--only major ones.
Summary: I use this to go geocaching, it may seem like an overkill but I really do love it. The only thing that I don't like is that you have to download the geocaches to the machine, instead of just having them there. It is already downloaded with geocaches but to far away for me to use.
Summary: My brand new, barely out of the box unit will only power up if plugged in to the wall or car jack. It will not recognize the battery power (I changed all the appropriate power settings). Apparently, this is a known problem with these and other Magellan units. Even so, Magellan is a little stinky about owning up to the problem. All units with this issue should be replaced regardless of the warranty status. Period.
Summary: I bought the eXplorist 510 because it had a built in camera & recorder despite the fact there were some bad reviews. The unit is hefty and the camera & recorder are OK, but the GPS has serious problems. Having used Garmin GPS's for the car, the Magellan menus are very confusing as many people comment on. I also experienced what some reviewers wrote that it drains batteries very fast. In fact I found out it drained lithium batteries overnight even when turned off.
Summary: While I'm no guru on GPS devices, I consider myself relatively savvy when it comes to gadgets and electronic gear. I bought this for an upcoming back woods backpacking trip, thinking that it would be at least a small upgrade on my smart phone's GPS app. I couldn't have been less right. First, if you plan on using this for hiking, don't expect a lot out of the box. The stock maps that come preloaded on the device are a watered down version of most automobile maps.