I owned a CS34 last year, now I'm shooting a Nitrum Turbo "and I've shot the 2015 CSZT line as well"....With the exception of the Turbo series "and the new Turbo cam" the ZT roller guard is the only difference on the Carbon bows for this year "the 30 & 34"... Now, the ZT roller guard is a cool little feature and it does do what they say it will do, reduce some torque in the cables....But with my 2014 CS34 I had last year I never had 1 tuning issue with it and the bow shot awesome for me. Now as far as which to buy, price is gonna play into this...If you can save a ton buying the 2014 and you don't care that the resell value is gonna be lower on it then go for it....If the price between the '14 & '15 is pretty close just buy the '15 cause if you decide to sell it within the next year the resell is gonna be better on it. As far as the overall performace & accuracy between a 2014 & 2015 CS 30 or 34, your not gonna see any difference there imho.