Actually both of them are better at thier place , At one side bitcoin which is our life and we spent our time and hard work to get it and other side is the bitcoin cash which will be new coin that will be generated by the same technology .
So I think bitcoin will be more better to have instead of bitcoin cash .
But as here we are getting the both without effecting the other one , so why not to have the both coin .
And also here we can think that we have the option to get a coin to buy in the very starting which is like the bitcoin ( infcatly from the same network ).