The Remington 7400/750 is legendary alright, . . . . for all of the wrong reasons.
I've never shot a Saiga before, but I'll bet you can fire 100 rounds through it without a single hitch, as opposed to having to scrub the chamber out every 20 rounds or so to keep it from jamming.
Every time Remington brings out a new incarnation of its semi-auto rifle, they loudly proclaim that its an "improved" version, which means they are trying to prevent it from jamming like its prior version. The newest version is the third in the line by my count.
I hunted in West Tennessee, and North Mississippi for 30 years, and never saw deer hunter carry one. I've hunted in the Shenandoah Valley now for 5 years, and have never seen a deer hunter carry one.
I guess the affection for these rifles must be a regional thing. The northeastern states perhaps? I am sure that some folks have had good experiences with these rifles, but it seems to be the luck of the draw.
Mannyrock