I've used both tracks...an Ice Ripper XT on my Nytro and currently an Ice Attack XT on my Apex. Both tracks are a great alternative to a lightly studded track, but don't expect off the line performance on ice.
If you look at the TracksUSA website, you can see the differences physically between the tracks. The lugs on the Ice Attack are firmer than the Ripper, plus the lugs are more paddle like, which apparently is better in loose snow.
I can't give a fair comparison performance wise, because the Apex and Nytro are different animals, plus track lengths were different between the two. On the Ripper, I had over 9000 km and the track still looked pretty much like new, so durability is there. I have almost 4000km on the Ice Attack and there are several threads exposed on the edges of the track. I don't know if this will be a problem durability wise...time will tell. Else all the stud tips were there and still sharp on both tracks.
