Landing an irs quad is actually easier than a solid axle. If you come off a jump crooked on an sa quad, the landing is harsh, and you could have the handle bars ripped from your hands. However, landing crooked on irs is not an issue. The reason irs isn't popular for mx is they tend to roll (body roll) in turns, and they are heavier and more complicated. IRS on sport quads is best suited for cross country. Good or bad is simply a matter of personal preference.
p.s. Honda's 700x "sport" quad weighs 65 lbs more than Polaris's.