Its very good indeed. I have it on my Nokia 5800. I have the whole of the UK at 1:50k, which at about £140 I thought was a bargain. I can bluetooth ridden routes straight to my Mac and upload them to ridewithgps.com for playback. Likewise I can plot a route in bikehike and upload it to Viewranger very easily. The program itself is easy to use but has a multitude of options should you wish to dig. The UI is very customisable. I've only used it for rides up to about 60 miles but have had no battery problems - after 4-5 hours the bars are still showing full. Its not a serious training aid like the Garmin but it probably is the best OS/GPS combi on the market - I had a Satmap and that’s stoneage by comparison. The only unsorted bit is a handlebar mounting, but I keep mine in a pocket and refer to it when stuck. Dahon have a very good iPhone waterproof mounting. Support is fantastic - my few queries answered by the developers in minutes and the program is regularly updated foc. Why not register for a free trial?
