The only downside is remembering to take it out of the aircraft,
I have a 2000 which I used to use with my iPad. I lost count of the number of times (in fact make it every time I used it) that I left it stuck to the top bit of the windscreen. I eventually wrote in red in big letters on my kneepad 'Get the ******* Glonass.'
I still used to leave it in...