On Heroic. It's actually pretty fun because it isn't [i]too[/i] hard but it still makes covenant much scarier. Also, anytime an Elite whips out a Concussion Rifle, your life will be hell for the next few hours as you try to kill him. And Hunters are almost unkillable. You know what, AMA.
Halo Reach is up there with my favorites within the Halo series. Hopefully a remake for Xbox one comes along so I can visit it again.