They're easy to apply. They're water slide decals, so if you've ever built a model car, train, plane, etc, you already know how to do it. On flat surfaces, they go on virtually trouble free and don't trap much air.
Curves are a different story. It's hard to get the decal to conform to outside curves without bunching. If you think about it, it makes sense. It's why we use darts in our clothes. Even though I used some Testors brand decal solution left over from my model building days, I still had to strategically slash the decals to get them to conform. It doesn't stand out, but doesn't hold up to scrutiny, either.
Here's a close up of the polished badge nestled within a decal. I don't have pictures of the finished decalling because I put on the first coat of clear today and I don't want to disturb it while it's drying. After another coat and some polishing, I will post pictures of the completed paint job.