If you're building a big kit, and I mean a BIG kit like a 1/200 Missouri, then you NEED this. In my case Trumpeter's Missouri kit actually needed almost the entire two bars to fill in weak areas and mold errors. If you do use this keep in mind that once it cures, it's like a rock. It's very hard to sand, so if you're one of those people who leaves a bunch of putty sticking out... good luck. It also works well for making hollow areas of your model heavier. A heftier model just feels higher quality, so I use this often as just dead-weight.

With some of my Revell kits of older vintage. (real old molds like the 1/426 Arizona) i've used this quite a bit to fill gaps. It's real easy to use, doesn't shrink unlike Tamiya putty (although Tamiya is better for some tasks) and is real easy to use to make custom pieces and fill large gaps. Be sure to mix both parts REALLY well though so that you don't get soft spots.

Just tried this stuff for the first time while building a USS Constitution. Had great results by following some of the pointers found in these reviews. Make sure you blend the two together well, and try not to leave a lot of excess that will need to be sanded. When dry,this is very hard and will take more than the usual amount of sanding,but I think that is a plus.