two part filler, like the evercoat you show, are great because they do not shrink, but if you buy off/discount brands, sometimes they are quite porous and you have to use a load of primer. They also do not "bite" into the plastic and if you do not rough up the surface, may pop off later in your project. I will say that I use the stuff you show above, but I also use spot putty for smaller work, and even mister hobby dissolved putty for things like ejector pin marks etc. I even will use melted sprue when needed. Essentially saying, no one putty for all uses, find what works for you.