George:

I'm using the AirMap500, and like you, considered the 1000; however, in a 150, if you want to change your mind, you have to step outside the aircraft. Thus, size truly does matter. Just thought you might want to condsider that factor! If you'd like, I can send you a great shot of how you can make an attachment which works fantastic.

Thanks, Herb Rose, N5793E; KZER