Pros are, it's a lot eaiser to clean off. Works just as well (once it sets and if you applyed it correctly). If you have the 9.75" rear end, it's hard to find gaskets for them (at least I could not find any).
Cons are, it involves a lot of extra time waiting for the stuff to set up and all, but I figure that's what BEER is for!!
Helps if you have a garage to do the work in and you have other chores to do while you are waiting for the stuff to setup and don't need to drive the truck for awhile......
I use the red gasket maker stuff. Spread a bead on the cover, circling each of the holes and let it set for about 15 minutes. Put on diff and hand screw the bolts in a criss cross pattern to get even pressure on it and only tight enough to get the stuff to just squeeze out. If you torque it down at this point, it'll just squeeze the stuff out and you won't have any "gasket" when it sets up (personal experience with this one.....
Let set for awhile (I usually wait an hour now) and then fill with lube. You can also tighten up the bolts a bit more at this point too.
After 24 hours, you should be able to torque the bolts down and you should be leak free until you take it off again. This is what I did the last time I had the cover off (had to replace an axle seal) and it's been leak free ever since.