Silicone packers, unless they cost hundreds of dollars, are NOT as realistic as cyberskin packers (unless you're referring to the cotton candy pink ones). The silicone prosthetics which you guys might be thinking of are gel-filled and made from different silicone than the Mr.Right or the Bella. The latter ones look like a single piece of uni-colored plastic, they're heavy, they don't give at all, they don't pass a grope test, they often don't sit well in your pants...to sum it up, i was thoroughly disappointed. The only pro i can really think of is that they can be sterilized by boiling them in water.
A cyberskin packer can last you a long time (two years of daily use are definitely possible).
If you've seen the peecock, the Mr.Right and the Bella look pretty much the same (same weird sheen, colors not looking natural), except for the hollow part of course.