We've had a Nature's Head for nearly a decade. We don't have "guest problems" partly because we get few guests and partly because we've got it set up in a little ensuite in an unused corner of our bedroom. That leaves the main toilet (an RV toilet) for guests.

Having worked with sewage in the past, dealing with the contents of the composting toilet is almost pleasant!

This size of system isn't for everyone, but one of those "family sized" models with a separate chamber and urine diverted to sewer plumbing or french drain that also handles grey water should be a no brainer. One that we looked at even used the weight of the user to automatically open the flap, eliminating most "guest problems".