Normal
I already wrote about the problems with IMDBUrl and why it's bad to be guided by it. The only thing that is supported by almost all grabbers is IMDBID (but not all). I.e. variant Title, IMDBUrl, IMDBID will not always give 100% results because every grabber is unique and works with its own dataset. But only IMDBID will give more or less stable variant from all these variants and if grabber is well designed you can get result close to 100%. In general (if memory serves me correctly) all grabbers that I have changed give results close to 100% in case of IMDBID.