I've had mud flaps, mud guards and Rock Tamers.
I had the mud flaps because they were required. They were ok, but could be a pain, especially backing in to a parking spot. To be effective, mud flaps have to hang fairly low which puts them at risk of being trapped between the tire and curb when backing in to a spot - this can tear them off. Uneven ground, even snow banks can present the same risk. As soon as I could I switched from mud flaps to mud guards by Husky. I really like them but they aren't really going to protect much beyond your exhaust pipe tips - and that not very well. They are more for aesthetics than true function. The Rock Tamers that mount to your hitch can be more effective than mud flaps alone due to the tendency for tires to kick debris up in the air at such an angle the mud flaps don't always catch it, or if the debris is heavy - like a chunk of metal - the Rock Tamers can help block the camper. However, if your truck is dual rear wheel, the Rock Tamers (or any flaps mounting to the hitch) are going to stick out beyond the ends of your bumper - creating a knee/shin hazard and generally looking ugly. I have seen some guys take mud flap material and attach it directly to the inside of their bumper similar to what you see on the back end of the fancy class 'A's. This can be a lot less expensive than Rock Tamers and just as effective, if not moreso.
In the end, the most effective way to protect the front of your camper is to avoid running over road debris.