From the Fermentis Website : "A well known English ale strain noted for its fast fermentation and rapid settling. Used in the production of a wide range of ales including English ale styles."
Safale S04 is a good all-purpose yeast for producing all styles of English beers as well as any other beer where you might want a somewhat fruity yet clean finish. This yeast folcculates well, which will help in producing a nice, clear beer given the proper time to settle out. The temperature range given on the Fermentis website is a very generous 59 to 75 degrees F. This can be helpful to ale brewer who may be at the mercy of a basement or other space.
Using this yeast is simple. There is no starter required - all you have to do is rehydrate in sterile water for about 30 min. before pitching and you are ready to go. They say you can just pitch this stuff dry as well, but I would recommend the rehydration route as it gets the cell walls elastic and ready to accept products needed for healthy reproduction once they are in your wort.
All in all, I find the Fermemtis yeasts to be of good quality, and I have had excellent results.
Typical Use : English Style Ales, Cask Ales, Any beer with a clean yet fruity profile
Flocculation : Medium to High
Attenuation : "Medium" per the Fermentis Website
Ideal Fermentation Temperatures : 59° to 75°