I Have connected three different types of hose to 3 different typs of holes in the ground and will thus comment:
The hose like pictured above (Threaded coupling) if used with a threaded sewer inlet works well but the joint between the elbow and the threaded adapter.. not so well in my expierence.. Likewise there is a smooth (not threaded) Stepped adapter you use with the sewer donut, same complaint, the joint between the adapter and the elbow is a problem
I've used the Tethford Smart hose.. the joint between the elbow and the adapter has a self locking feature that seems to work rather well (Amazingly enough).
I got a couple of hose buddies
http://www.hosebuddy.com/ and they work well (used to have 2, lost one). and are easy to carry around.
Oh the third kind of hole in the ground is the one with the brass flip cover.. Those generally LOCK ONTO the elbow (if it has a male hose fitting on it, plugged) and work very well. But I find that one mostly at dump stations not campsites.