I have tried my best to like SpotCrime because I think the people behind it hearts are in the right place and because it covers large areas of USA and parts of the world. But the lack of information about where specific data have come from and the non-standardisation of data between different places makes my confidence in the accuracy, comprehensiveness and the appropriateness of the maps very low. They are first generation crime maps for the public and of the not so good sort. The quality control is not there. There may be some quite good individual cities but they are more than let down by the bad ones.
The software supporting the site is good though. SpotCrime seem to be developing mylocalcrime.com. They claim it is fast and they are right - impressively so. The software behind reporting a crime is good. The way in which you specifically locate the crime on GoogleMaps to give highly accurate co-ordinates is something all police forces should duplicate.