I ride a 162 apex for work and a 174 T-Nytro for pleasure and I previously owned a 174 T-apex. If I had to choose, I would go with the Nytro. It took a little (only a little) getting use to the nytro at first, but I now would not go back. Both have pros and cons but I think the apex chassis is just to outdated. I rode the work apex today in the mountains and every moment I wish I had a nytro.
As for things to consider:
1) The nytro tends to get hot and sometimes overheat, but I have never overheated an apex. If you buy either, put ice scratchers on and good hyfaxes. Vents are a good choice for the nytro and possibly an upgraded cooler if you trail ride more than not.
2)The apex a-arms and spindle housings are very weak and they "will bend" if they take a moderate hit from a stump or rock. I replaced or fixed 3 arms and 3 spindle housings in 5 years. However the nytro front end has pissed some riders off also, but not me yet.
3) The 162 apex is just about 700lbs wet and the 162 nytro is ???? I forget, but it's lighter.
4) Choice of motors----apex!
5) Choice of 162 stock suspensions----nytro se
6) Maintenance/repair choice---nytro
5) Track length--shoot I think 162 is too short!
hope that helps
good luck