I own both an Omega and a couple Knight Disc Extremes. My Disc Extreme in 50 caliber is my favorite. The two piece bolt is easy to dissasemble and clean and takes only a little longer than my Omega. My Extreme 50 with an inch shorter useable barrel length (25 1/2" vs 26 1/2" for the Omega)is 2 inches longer overall.

Pesonally if I were getting into muzzleloading today I'd start with a Knight Disc Extreme or Elite if scopes are legal. The reason? Cost. A lot of folks have sold or are selling their bolt actions. You can pick up a $500 gun for as low as $200 or less. Just because they're not as popular as they once were doesn't mean that they're not good rifles.