In my area (elevation 4500', short cold growing season, little rain but all irrigated, usually rotated with other crops) nothing I've seen grows like fescue. We plant pure grass stands, and usually only grow it for 3-6 years before rotating to other crops. The forage yield I see is about 50% more than any other grass I've seen. We fertilize fairly heavy, and rotational graze it. I am very happy with it. As fertilizer prices rise I am tempted to add a legume to the mix, but I feel the yield loss, weed issues and worry of bloat still outwiegh the added fertilizer expense.
Far as endophytes go, never had a problem, but all the varieties I plant are endophyte free. I know some older pastures I lease are not, but never seen an issue. I bought some hay standing one time that I knew the grass supposedly had an endophte problem, which is why no one grazed it off. I was a nervous little pup feeding that stuff, but again never saw a problem. I have heard it can be worse in other climates.