Good question, and one I get asked a lot, but to be honest really, it’s down to the individual to answer this one themselves.
We are all different in our tastes so what is good for me may not be good for you etc.
I guess the best that one can do to answer this is to give you some good points on both instruments and the final decision will be yours, but what I always recommend is for you to go to your local music shops and try as many different types of both the piano and piano keyboards as once again all are different.
The Piano alone can be made to sing like a bird or sound like thunder on a bad day its such a versatile instrument that really you can create any mood with it.
The Keyboard comes into its own really for people who like to arrange music and play around with the sounds it also is fantastic for adding say a full orchestra as backing to your solo piano playing