It's really what you want the zoom lens for
I have a cheap as chips sigma 70-300 zoom which is great as long as the the lighting is decent
it's all down to budget at weather or not your going to use this lens alot
a canon 70-200 f/4 L will set you back around £550 stg if thats the route you want to go
here is a few shots taken with this lens(the cheap sigma 70-300 that is)

