I have done a few different types, some easier than others. What are your opinions? I found freestyle forms like GKR and kin bushi ryu easier to learn. What about u?

What might be easy for one might not be easy for another.
If a style puts a lot of emphasis on fitness, that might be too hard for an asthmatic.
Where as, a slower style might not stimulate the more active karate ka.
The choice then is yours.