Got one of these just before Christmas. Thought people would like to know it works fine on my Defender which has a heated screen, despite rumours to the contrary. See it's down to 399GBP in PC-W*rld in the paper today.
Nice bit of kit - even knows the names of the greenlanes I use... and the sucker thing for the screen seems very secure even off road. Plus I have succesfully downloaded the UK speedcams database, which also works well.