I tried them both and really couldn't find much difference as far as application goes. The Super-fil definitely sands easier than the Aeropoxy, that doesn't mean I like it better just a observation. I know that AeroPoxy is not real easy to sand, but knowing that ahead of time you try to put the fillets in so that they need very little sanding which is not real hard to do. The shaping is done while it is wet and pliable. I actually found it a little easier to use the AeroPoxy of course I am used to it. This is my first try with Super-Fil and it really presents no problems either. I think either will work just fine. I think the most important thing with either is patience. The Super-Fil is light blue and the AeroPoxy is a reddish brown, it looks almost pinkish in the picture. I find the Super-Fil sands easier than the AeroPoxy. But for me that really doesn't matter much as I don't plan on sanding very much anyway. IMHO They both are really good. I think talking with someone who has done it is a big help. Tape off the area to be filleted to prevent a mess on the rest of the plane. Also tapping off the area to be filleted is a big help in keeping the fillet width uniform as it acts as a guide for you. I used an ice cream stick to put the material in the corner. Bob Reeves suggested I try a marble glued on the end of a stick. It produced the best fillets I have done especially around the leading edge of the wing. Clean up any excess off your guide tape. Have paper towels and alcohol available before you start. If you not happy with the looks of the fillet after you put it in, just wait a few minutes and then put some alcohol on your finger and you can run your finger over the fillet and it will smooth out any rough spots. Make sure you have alcohol on the full length of the fillet before you start dragging your finger over it so it will slide easily. If it's not wet it will stick to your finger. No matter how bad it looks going in, it will shape up nice with a little finger work. This works for both AeroPoxy and Super-Fil. I like them both and will use each in the application that suits it best. Kind of fun to play with this stuff. I find the AeroPoxy to be a little smoother than the Super-Fil, not that it's a difference that makes a difference, it just seems to be a little creamier. I think because of the coarseness of the Super-Fil it might give a better grip for the primer.