I am looking to buy a Z Force in the next few weeks and I am trying to decide between the 500 and the 800.  Need opinions of if you think it is worth the extra money to go ahead and get the 800 or does the 500 offer plenty of power?  THanks for any feedback

I have never been in the 500 so i cant comment on its power.  But i can tell you from experience in other motor sports rides.  Go with more HP if you at all can because it cost WAAAAAAY more money to try to get that little bit of extra HP out of the smaller engine later.  I have made the  mistake before thinking "I dont need that bigger engine" and within a month im kicking myself in the tail end wishing I had just got it and spent the money up front.  IMO if you are asking if the 500 has enough power then power is a concern to you and something you are wanting.  Go for the 800.

I had the CF500 quad and after one year traded it for the CF800 quad. I found the 500 didn't have the power I wanted and I am very happy with the 800.

[2015 Z Force 800 53/Trail EPS]

I'm with everyone else. If they had made a 1000 when I bought mine, I would have gotten it over the 800. Do the 800..it's only a few bucks more. 

It also is going to depend on what kind of riding your going to do. my advice would be to test drive them both and see what you think.