Better efficiency hands down belongs to the clone. You can run it on either, but typically SLP or just LP (ninja pro with shims removed) is the best input for newer guns. Reliability is similar if you maintain them both appropriately. As for easy to work on... well, I don't consider either gun particularly complicated so it's kind of relative.
I will also mention with the new GTi board the clone is getting even better. (I'm hoping full details are going to be released soon.)