Hi, thanks for the tip, that worked perfectly.
When I played around with smart list rules for the ratings field I had the impression the field is defined for integer values. Nonetheless when fetching data from IMDB the field is filled with something more like a string (e.g. "7.7 (118,659 votes)"). I don't know if this is possible with all data sources but I think you should either condense whatever you read from a data source into a numerical value (which is what I do manually now) or redefine the ratings field as string value.