Left my comments. Unfortunately, the market doesn't allow enough text to really leave meaningful feedback. So, in case the developers are reading here, too:
As others have stated, the program simply MUST allow the maps to be loaded to the SD card. I'm unable to download the maps, so I can't evaluate the program at all.
And there needs to be an option to download files this large over a wired connection and sideload them onto the phone. Not everyone has a WiFi connection available, and not everyone has unlimited data.
Frankly, this is so obvious, I'm amazed the developers haven't already fixed this. They're on version 10, I think, and haven't bothered to address this yet? Unbelievable.