Yes I have used it a couple of times and as you said seems OK. I saw a comparison between a phone app,looked a lot like Strava and a bike computer. The difference was quite a lot. The bike computer used GPS for speed not a sensor on the wheel as well. They said bike computers have much better GPS as that is all they are designed for. I guess GPS in your phone will vary between phones. Most bike computers are waterproof as well. Might have to borrow one and compare them.
