It came down to the Zumo and Nuvi 550 units because they are water proof, a requirement for my bikes. The Zumo clearly has several features the Nuvi does not, but was lacking in one critical area for me – battery life. The Zumo is rated at 4 hours, virtually requiring hard wiring. Since I use GPS on all my bikes, I did not want to go through the hassle, and the Nuvi comes with an 8 hour battery.

All it is lacking for me is the interface to enter addresses. On the Zumo it is more glove friendly. But other than that I could not be more satisfied. I use the Mapsource software from my Quest 2 to plan routes on the PC and upload to the unit. It is quick to recalculate and never loses a signal. I bought a RAM-MOUNT and it enables trouble-free and solid mounting to the bikes (just like they had done for the Quest 2).

If you don’t want to hard wire, this is a great GPS unit. Oh, and I bought a spare battery and keep it charged – now I have 16 hours – more than I’ll ever need for one day.

5 stars well deserved from this happy owner.

First, the good stuff. This GPS is quickly becoming an invaluable tool for long drives. I have been able to enter a street address as well as many restaurants, hospitals, and businesses then just click on “go.” On one trip, it correctly navigated reversing direction on a double-cloverleaf turn. A pleasant voice guides you and alerts you of upcoming turns. Miss the turn and the unit will patiently wait for you to realize your error. Then, after a while it will just recalculate your route automatically. It is also possible to tweak the routes by manually entering points to divert the automatic routing or pressing “detour” on the fly if you find yourself stuck at a railroad crossing. Custom routes can be saved. Waypoints can be sorted by category and new categories can be added. Photographs can be added, although I haven’t done much with this feature. Clicking on the top bar will display the route turn by turn. I found the routing quite intelligent and much prefer this unit over my last human co-pilot (but I hope that she never reads this review). This particular unit has a rechargeable battery and the unit can be mounted on an optional bean bag mount to just throw it on the dash instead of messing with cables. This makes it perfect for rental cars as well. It has four modes for driving, walking, boating, or bicycling.

Next, the so-so stuff. This unit does not come with any software. There is map updating software available which can be downloaded from the website, but there is no real support for uploading and downloading waypoint information. It is possible to use Garmin’s MapSource with this unit if you have an old copy, but the Nuvi 500/550 does not seem to be fully supported. After wrestling with it a bit, I was able to download points but not modify them. And, since the background map is pre-loaded, there is no background map for MapSource. There are features which are missing, such as the ability to turn off poi’s (Point of Interest) labels or the ability to modify the lat/lon of a point once it’s created. It does not come with an a/c adapter or usb cable, but they are both available from Garmin at an outrageous price. Thankfully, the USB cable is a standard mini-USB and you may already have the cable you need at home and not know it. Once you locate a cable for it, it appears as a disk drive on Mac or PC without additional drivers. I added a microSD card, which appears as a second drive, but haven’t found a use for it yet.

Finally, the ugly stuff. 9 times out of 10 the street address translates to lat/lon coordinates within a few feet of your destination. But, once in a while, it’s a bit off translating street addresses to lat/lon and there is no way to modify this information (at least, not easily). The user data file appears on the unit as Current.gpx in xml format. However, this file appears to be only a copy of the real one. Any edit or deletion of this file is simply undone when the unit reboots. And, since there is no software with the unit, you may have to just settle for arriving close to your destination instead of it bringing you right up the driveway.

If you really want to dig into the guts of the system, the best way I found is to generate one waypoint and use the data in the Current.gpx file as a template for your personal waypoints. I created several custom .gpx files in xml format with notepad. The lat/lon can be entered easily by using Google Earth, right-click on the new point (which may first be dragged to exactly where you want it) and paste the information into notepad. When you’re done, you will have several gpx files (xml format) which will be incorporated into the unit’s memory when you reboot. The bad news is that the points must be deleted through the menu system (not a big deal) and the decision to re-load your personal files is apparently determined by the file creation date. Duplicate points or database corruption is possible, but easily undone.

Using this method, I was able to correct the lat/lon of a waypoint which was 4 houses away from the correct address. I found a more accurate location in Google Earth, deleted the point from memory, and re-loaded it through my custom gpx files. It’s actually easier than it sounds since the only software you really need is notepad. I’ve added many new waypoints by copy/paste. To create a custom category, simply name it in the appropriate tag. Routes, I imagine can be dealt with the same way but I find their format too difficult to create or modify by hand.

There’s many missing features which I’ve found on other hand-held units. There is no way to save and load personal files, other than doing it by hand. The satellite tracking and fix information has been replaced with the same type of “bars” you have seen on cell phones – easy to understand but less information. It has a touch screen, but it is not very precise, tends to make mistakes, dragging is miserable and the resolution is very bad… but, all of this is acceptable since most of the time you only need to press a few spots on the screen to start navigation. The cleverness of the unit really outshines the shortcomings of the display.

All in all, a wonderful travel companion. It’s intelligent, useful, and will keep you company on long trips. If you’re a gps hacker, you’ll find it just flexible enough make it do what you want, but it will make you wonder why Garmin makes us go through so much misery to tweak or save a waypoint to your pc.