Well, i guess it depends on the riding you do.... we have three 4 strokes.... 07 attak, 09 xtx, and a new leftover 07 phazer fx.....
if you ride the tight and twisties, there isnt a more fun sled than the little phazer... well you know about the phaze, u already have one.... now the attak, wow gobs of power nice ride..... but the xtx, a totally different animal.... some ride characteristics of the phaze and some of the kick of the attak....
the nytro is a really good sled.... we havent yet got the wifes xtx dialed in yet, but getting close, made some more more adjustments and its time to try her out some more.... the nytro definattely has the pull for the longer staighter trails over keepting the phazer pinned, and there is no comparison in the loose or deep snow.... this in my opinion is where the phazer really shows her lack of grunt...
still a hard decision, depends on what your after... good luck.....