I am trying to make a decision on which to buy. The Pro 106, PSR 500, or PSR 800. I am assuming the only difference between the first two and the 800 is that one has the SD card and the other two you have to manually program. I have read that the 106 is difficult to program but have found nothing on the 500. Looking at money, the 500 and 106 are cheaper but I want to make sure the quality of what I am recieving is great. Anyone have any advice on these scanners?