Severak x vs y threads lately for some reason. It is difficult to judge because everyone sees things differently. All I can give you are my conclusions based on my own test data. Some quick comments: Pan F+ is inherently more contrasty than Delta 100. This can of course be controlled/altered but I'm referring simply to the film's "natural" characteristics. I have found the relative graininess of the two films to be virtually the same. In fact from an image structure perspective I find them difficult to tell apart. So I wouldn't characterize one or the other as being "better" for a specific type of subject. I'd select based more on the type of lighting/contrast conditions most often encountered. Of course there's also the difference in speed.