I prefer trail or lightly packed gravel first & if I'm stuck running in town I will do 50% on asphalt 50% on the grass next to it. Sometimes my legs respond well to the pavement & enjoy it, but for the most part trail/grass is easiest to recover from. I also do at least 30% in VFFs.

While I may have my preferences I'm glad I get the chance to train on it all because I think that helps with overall fitness. Makes me fast and comfortable on hills & flats.