Fuji Provia 400X is a slide film aimed at professionals who want fine grain and sharpness in their photos. The film is very good for push/pull processing which means you can shoot it as if it were an ISO1600 film.
I like the results when this film is cross-processed. The grain is no different to that of ISO100 films such as Velvia 100F. The colours are lovely too - a very subtle green-shift is present, but it's not overpowering - unlike most of Fuji's other films!