Summary: Visit the Garmin Connect forum for information on Garmin's recent move away from Google Maps to Bing maps. Many, many user complaints about the switch, and Garmin's response has been to ignore the complaints.
Summary: There is no reason to buy the 705 unless you plan to then spend another $100 on maps. The "navigational" features on this GPS would maybe be impressive if it was 1492. But if you already know what continent you are on, then the satellite/basemap is useless. So you can either get the 305, and save several hundred dollars, or be prepared to send Garmin more money before the device will perform any of the functions that the 305 cannot perform.