The difference between the csx and the cx is that the former has a barometer and electronic compass. I bought the model without those.

My main reason is that I will always have a separate magnetic compass anyway, along with a map as backup, so I don't feel I need another one built into the GPS. I also have both compass and barometer in my watch. To be honest I don't really trust electronic compasses anyway (I don't know what the GPS one is like).

I gather the barometer helps give a more accurate altitude than GPS alone, but that's never seemed important to me. I guess if you need it, you know you need it. In the UK once you know your location you can pretty much get your altitude from the map.

So I didn't feel I would get much benefit from the extra sensors. I don't like paying for things I don't need, and the difference in price is about £40 in the UK, and these things aren't cheap to begin with. (You can buy a lot of beer for £40.)

The other thing you have to watch is battery life. The extra sensors take electric power, and I don't think you can turn them off when you don't need them. According to the website we're talking about the difference between 30 hours and 20 hours.

Obviously your milage may vary. There's always the thought that having the extra features could one day save your life. However, maybe that's just paranoia making you spend more money. I've had the Garmin 60cx for about a year and don't regret getting the cheaper model.