Sp/sx is smarter with their sx, more careful and guarded. They wait until they're sure they can trust someone before letting them into their inner sanctum. Sx/sp will may let somebody in on a whim, then freak out about it and start a big push/pull game. Also, in my experience (though not always true) sp/sx's are more relaxed about casual sex. (That is not a slam on their morals, it's honestly something I wish I could cope with better, it would make life alot easier.)

Sx/sp's get more freaked out by their intense emotions/connections, though these are what they crave most. They love to connect, but the fear of loss can be quite intense, so the self pres kicks in. The person is then torn between approach/run away/go for it/protect the self. It's a very uncomfortable dynamic to feel or watch.