I have implemented a ROR site map generator in my site. It generates/descripes much more URL links (for my site tripple and more) than other tools I have used before. Are the number of pages and/or the ROR format important for better crawling? Till now I can't see difference. And it is not said much here http://forums.digitalpoint.com/showthread.php?t=134334&highlight=ror
If these tools are based on web crawlers may be different tools are powered by different crawlers with different skills.... or bugs!