I guess it depends on your riding style, and the terrain you ride. Steep, loose, rocky trails, rock crawling, snow covered trails, there's just no comparison between OEM and HTR's. If groomed trails, or mild riding is your style, one might not notice as much of a difference between OEM and a set of quality tires. They suit some folks just fine. Others, not so much.
Meh... whatever floats the riders boat I guess. I ride a bit of everything and honestly can't tell a bit of difference. To be fair, I only have a few hundred miles on the HTR's, so maybe when I go back to Drummond Island and do the steps at Marble Head, I'll make it up faster / easier... don't know yet. Groomed trails and deep sand hill climbs, they ride the same. I haven't noticed any difference in their handling in snow... been out riding (not on the trails) in the 6 or so inches that we got last weekend and they seem to handle about the same as the PXT's. I'm not a deep mud rider, so I'll never know if there's a difference there.
I can say however that they're a bit smoother when riding over obstacles, but I think that's mostly because of the larger diameter.
I'd like to see some honest blind tests (not sure how that would even be possible) to see if people can ACTUALLY tell the difference, or if there's just a lot of confirmation bias in the forums.
All I'm saying is that after riding both the stock and the HTR's, there's no way I'd spend $500 to switch out stock tires to HTR (or any other aftermarket tire for that matter) before the stocks are worn out, damaged, or unable to do what I need them to do. There's a lot of other things I could to with that money.