As a straight adhesive, polyester resin would be considered too brittle. It is also hazardous, and must be used in a well-ventilated area. The activator is also hazardous. It seriously damage eye tissue if you get it in the eyes. It really isn't the best thing for general building. It's a very good product, though, for specialized areas, such as preparing a surface for paint, adding strength in localized areas, and so on.

Also, it makes a good substitute for epoxy in many areas because it's lighter.

As for epoxy, just because its smell isn't as offensive as other materials doesn't mean that it doesn't have some hazards associated with it. Inhalation of the vapors can still be toxic, and you need to be using it in a well-ventilated area, too. I know of a person who is so allergic to epoxy that just being in the same, large room with uncured epoxy caused severe physical reactions. Tolerance of epoxy usually decreases as exposure increases. People who have done a lot of building of molded homebuilt aircraft have found themselves sensitized to epoxy during the project, and wound up having to use more and more safety gear to protect them against reactions to it.

Just about the only glue you don't have to take special precautions with is the water-based aliphatic or casein glues, such as carpenters' glues and ordinary white glues. They are safe enough that you can give them to small children to play with.

You can easily check this out by doing a google search for the MSDS of any product.