I use whatever is needed...Gorilla tape, plywood, foam board and I really like this stuff:
Exterior Rated Touch 'n Foam
I haven't seen the critter repelling foam, but, I'll have to take a look whenever I'm in the "big city" at a Home Depot (we live way out in the sticks)
No Rust Critter Block
As opposed to regular steel wool, this stuff won't rust or leave rust stains in its wake.
Use whatever is most applicable (you wouldn't want to use plywood to repair a gap in the fabric under the trailer, etc.). My only word of caution is to stay away from silicone. Silicone migrates and while it is good stuff for an initial repair, once the silicone is there it is darn near impossible to remove so that another application will stick in that area. That's why the stuff for RVs that the repair shops and manufacturers use doesn't contain silicone.