I switched from the 305 to the 500 and so far I'm not real pleased with the way the 500 acquires the sat signal...or should I say DOESN'T acquire it. The 305 would find it in less than 60 seconds...the 500 is several minutes...and sometimes 5 or more. Even then it's horribly inaccurate. The 305 would get me to within a few feet, the 500 is lucky to get the same street! Anyone else having this issue? New firmware as of 6/19/12