I do use GIF Animator and Image Composer for different projects. At first I found the transition between using Photoshop layers to using Image Composer sprites a bit confusing. I especially enjoy the visual interface elements, and the variety and unique manipulation of brush strokes. The 3-D integration is also effective. If you are familiar with using Office products, you will find the interface easy to use because it is so similar to other Office products' functionality.
Most designers are creatures of habit when it comes to tools.
We get used to how graphic manipulations are handled in one application, then become bewildered by new approaches to working with graphics. I find it fascinating when a tool challenges my own stubbornness in how I assume images should be treated and what type of interface we expect them to be massaged within. Overall, you will use a combination of tools and technologies you are most comfortable with to get the graphics created, and to your client or audience, in the most creative, quick, and effective manner. Keep your toolbox full, and don't be afraid to try something new. Interesting tools and techniques pop up where you least expect them.