Mio amazed us a while back with the incredibly priced Spirit 685. A 5in screen sat-nav with European maps and RDS-TMC traffic never cost as little as £100 before. The Spirit 687, in contrast, is a more believable £150, but it does have a number of features which set it apart from its cheaper stable mate.
The Spirit 687 looks identical to the 685, with the only obvious physical difference being the AV input microjack on the bottom. This is primarily intended for connecting a rear-facing camera, to aid reversing. However, the supplied cable sports regular composite video and stereo RCA audio inputs, so you could conceivably hook up any video source with these connections, such as a portable DVD player, should you want to entertain the kids or watch a movie in your car once you've reached your destination. Like the 685, the 5in screen has a resolution of 480 x 272, which is adequate but not up there with premium models, and fairly limited for video. We also found that some video inputs gave the 687 problems, such as the downscaled video signal from a HD camcorder. The device couldn't keep up with the video and lost its picture.
The remaining differences are inside. The 687 comes equipped with twice the memory of the 685 - 4GB instead of 2GB. Both are supplied with maps for 44 European countries, but the 685 only has 23 countries preinstalled, and if you want to install any others from the DVD you will need to remove existing countries first. The 687 has all 44 countries stored on board out of the box.