Having grazed cattle for many years in Missouri on fescue, I will chime in.

Fescue will take over the weeds in a pasture including the tough ones.  It basically crowds out everything, legumes included.  However, if you broadcast red clover on the snow in Jan-Feb, it will thrive in the summer months when the fescue (cool season grass) is kind of dormant.  The clover will fix some nitrogen and can be baled or grazed.  It's a winning combination and very easy to manage.

Most years the fescue can be combined for seed and still make a hay crop.  The seed will pay some bills at a great time cash flow wise.  

It is important to start feeding the herd some Magnesium a month or two before green up to prevent problems from fescue foot.  If you do this you won't know what fescue foot is.  If you haven't feed the Mag-Ox first, don't turn out when it greens up!

For waterways, spillways, or levees, seeding to fescue and leaving it grow provides as good a protection as you can get against erosion.  The fescue will lay down as the water flows and make a very tough mat of grass that withstands the erosive power of the run-off.  Nothing else even comes close to doing it the way fescue does.

It's possible to interseed brome, orchard, or timothy into fescue and get some return for the effort, but you have to keep after it or the fescue will eventually choke it all out.  With the introduction of the single opener no-till drill like the John Deere, it suddenly became possible and desirable to interseed the fescue every couple of years and have a full season forage program. 

Edit to add:  If you like to scratch chiggers, grow some fescue and walk through it on a rainy day when it is mature (tall).  Wear some jeans and walk it early in the morning so that you have the whole day to nurture the little fellas.  Then enjoy scratching for the next couple of weeks.

The Missouri chigger is no bigger than the point of a pin, but the bump he raises, itches like blazes, and that's where the rub comes in.  (John Henry Stroup)